Well, as I said earlier - unlike other time travel-based films, this one never overwrites any of the timelines, another one just branches off every time they travel back.
What is that based on? That notion undermines the entire premise of the film series going back to the first T-800 sent to kill Sarah before John could be born.
I just don't know why I should be excited for a movie that basically uses its time travel shenanigans to undo what happened in T1 and T2 and mash them together in a weird fanfiction-y way.
Yeah, fuck with T1 and T2. Not like they are considered movie history classics or anything.
Technically, all those would have still happened, even with the timeline getting overwritten. The current timeline could not exist if not for those events.
So, the quick tl;dr ('cause I'm on my phone), is somewhat what Tres said in his part 2. The main discrepancy is that time travel in Looper is totally different than the time travel in Terminator. Looper is a single, self-correcting timeline. Anything that gets changed immediately propagates into the timeline. Terminator has Timeline A and the time travel creates Timeline B. You get a LOT of sense for how this works from TSCC, because as they keep sending people back, each person sent is coming from the version of the future that exists because of the changes that have been made after they were sent. Also, I asked the director of Terminator Salvation about how it was used in the film and got an answer that supports those underlying mechanics as well.
I'll probably draw out a little diagram, too.
(It might be a bit, 'cause I'm on vacation in Texas right now)
That still sounds like overwrites rather than splinters. =P Splintering implies both timelines continue to exist, and indepedently of one another (a la Marvel's alternate timelines, where even an averted future continues to exist as a separate timeline). Under that paradigm, traveling across time periods is equivalent to traveling across alternate dimensions/universes/realities.
I never watched "The Sarah Connor Chronicles," but the fact that each new visitor from the future comes from a future that exists because of the visitations -- and they all keep appearing in the same present era -- speaks to overwriting rather than splintering.
I think this movie will be watchable, having read various viewpoints on it, which has wet my appetite. The acting in the trailer is undeniably terrible. Hamilton's acting skills simply blow Clarke's out the water, and Arnie has totally forgotten how to say the "I'll be back" line. The accents are wrong. I hate all the cheesy fan service anyway. The CG is cheap-looking and simply not convincing. I'll ignore all that though, since I think the film could be interesting, in a "Salvation was interesting" way.
I like that they have an old arnold vs new arnold, so I will hold my judgement until it's here. The magazine covers are soooo fucking shit though so it left a bad impression.
FFS. Macintosh computers are shit. They somehow managed to hang all of Chrome at once, rather than just a tab, aaaaaaaaaaaaand I lost the writeup that I made. It was really in-depth and long and things.
Essentially the important bits are that the timeline splinters, and the upcoming future changes upon each new iteration of time travel, but those old versions of the future/Judgement Day that are averted/changed aren't overwritten, because the individuals who travel back stay in their original forms. For Example:
Kyle Reese from T1, who is John Connor's father in T1, T2, T3, & T4 came from a Judgement Day that took place in 1997. Judgement Day is now sometime around 2004ish as of T3 & beyond. Kyle Reese's version of the future doesn't come about in the timeline anymore, but it still happened for him to get there (see: Old Spock in Star Trek IX). Each future only sends back TWO individuals - one from Skynet & one from the Resistance in pursuit of that Terminator. Despite Judgement Day changing, the Kyle Reese who is John's father has always experienced the 1997-based Judgement Day (insofar as I'm aware). Skynet tracks the changes in each alternate timeline when the new future comes about, and that's why its tactics keep evolving (confirmed by the director of Terminator Salvation in a question that I actually submitted because this is the type of thing that I'm geeky as fuck about: http://www.mtv.com/news/1612172/terminator-salvation-director-answers-fans-burning-questions/ ).
That leaves this as the progression of events.
Timeline 1:
• Kyle Reese arrives from Timeline 1's future to protect Sarah Connor from the T-800 Model-101 sent to kill her, they have a kid - John Connor.*
- T-800 chip is left behind, and Skynet creates more advanced Terminators on the same Judgement Day, creating Timeline 2.
*Note: while the previous John Connor from the 1997-based future is Sarah's son, he almost certainly wasn't Kyle's kid, but the John Connor from here on out is.
Timeline 2:
> Prior timeline events happen:
• A T-800 Model-101 arrive from Timeline 2's future to protect John Connor from the T-1000 sent to kill him.
- They're defeated & Judgement Day is postponed, creating Timeline 3 where the Judgement Day happens in ~2004.
Timeline 3:
> Prior timeline events happen:
• A T-X is sent from the future of Timeline 3 to kill off John & his generals, and a reprogrammed T-850 Model-101 is sent back to stop it.
- Several of his generals are killed, creating a different version of the Judgement Day, Timeline 4.
Timeline 4(?):
> Prior timeline events happen (doesn't include TSCC insofar as I'm aware, but if it does it's a later timeline).
• Skynet sets up Marcus in the Resistance, and almost eliminates John Connor.
This all looks like this from our viewing perspective, and from the events in the current timeline:
• A T-800 arrives (from Timeline 1) to kill Sarah Connor.
• Kyle Reese arrives (from Timeline 1) and saves Sarah Connor.
• The T-800's severed arm & CPU are left behind (makes Timeline 2).
• Kyle & Sarah have a child - John Connor.
• Sarah Connor is committed into a mental institution, John goes into foster care.
• A T-1000 (from Timeline 2) is sent back to kill John Connor.
• A reprogrammed T-800 (from Timeline 2) is sent back to protect him.
• Sarah Connor & John escape, and meet Miles Dyson.
• Miles Dyson's research on the arm & CPU are stopped.
• Judgement Day (from Timeline 1 & 2) is postponed (creating Timeline 3).
• Sarah Connor dies of Cancer.
• John Connor meets Kate Brewster.
• A T-X arrives (from Timeline 3) to kill John Connor & his generals.
• A reprogrammed T-850 arrives (from Timeline 3) to protect John.
• John Connor's key generals are assassinated by the T-X (Timeline 4 is created with the same date of Judgement Day).
• Skynet goes active - Judgement Day occurs (July 25, 2004).
• John Connor & Kate Brewster survive in a fallout shelter.
• The T-X & Terminator are destroyed.
Essentially, they're not being overwritten, because if they were, each Kyle Reese//T-800/T-850/T-1000/T-X in the timeline would all be from Timeline 4, and would ALL need to be sent back every time becoming increasingly ridiculous and complicated. Instead, they're a part of the established history, and still arrive in the most recent timeline no matter what version of the future comes to pass. The only person that the Resistance sends is to chase after whoever Skynet sends most recently with its updated information building on past experience. This is important for what looks to be happening in Genisys.
Genisys just adds this:
• A (?) Terminator is sent to assassinate Sarah Connor as a child (and kills her parents).
• A Model-101 is sent to protect her from it (and raises her and begins attempting to attack the other time-traveling Terminators as they arrive).
Insofar as I can tell from the trailer & article I linked, the version of the future with Kyle Reese getting sent back IS from the old 1997-based Judgement Day. Most everything looks like it was taken from the unused storyboards of Terminator 2 designed by James Cameron: http://www.terminatorium.net/storyboards2.htm, and there's VERY careful work to make sure that all the details from the original are still the same - like Kyle's shoes: http://io9.com/terminator-genisys-got-nike-to-remake-kyle-reeses-sneak-1667369939
What I'm betting is that Kyle is from the 1997-based Timeline 1 Judgement Day, but the Model-101 that saves Sarah when her parents get assassinated is from a post-Timeline 4 Judgement Day. That's why he knows when all of the other Terminators are set to appear, and they're preemptively assassinating them as they show up in the current timeline. This also explains why it looks like Kyle & Sarah are jumping forward in time (and fighting the T-1000), but the Model-101 stays behind, and thus has grey hair. (From a filmmaking stand point, this lets us just start with the basics of Terminator knowledge as a jumping off point, and then teaches the changes as he learns them. This also allows them to use an older Arnold with the younger actors, and also not have to film everything in to look like it was in the '80s once they jump to the next event).
While each time traveling event takes place later chronologically in T1-T4, TSCC has dealt with leapfrogging events like this. They bypassed T3 in their timeline and
(Derek Reese and Jesse Flores remember each other, but not the same versions of each other, because they arrive at different times, and thus are from different timelines)
, so it's not surprising that the new film is using that mechanic for the current story, and if they're handling the time travel like it looks like they are, I'm the happiest. Ever.
Thanks to this for a couple of the details:
So, now knowing all that... educated conjecture about the film, re-watch the trailer and see if it makes you feel any differently about it.
Still reading this but some questions that I'd like to ask that popped up while reading and well i dont want to forget
Since the timelines splinter every time someone is sent back and each continue to co-exist (right?) does that mean the John we see in T2 might not even be the same John we see in T3? Same for the Sarah we see in T1-T2? *Nvm read more and its more clear that the splinters occur for future rather then the past/present.. right?"*
I kinda like this idea and it also helps me to take in something that always nagged me about Salvation. In T3 its established that Skynet was a government botnet gone self aware yet in Salvation it felt like Skynet was back to being an independent company like Cyberdyne with the way they reached out to Marcus. I havent seen either T3 or Salvation in awhile but from memory it really did feel like these 2 skynets were 2 completely different entities operating in our present time.
*Disclaimer I havent watched TSCC so idk if that adds anything to the different feeling skynets in T3 and T4*
Since the timelines splinter every time someone is sent back and each continue to co-exist (right?) does that mean the John we see in T2 might not even be the same John we see in T3? Same for the Sarah we see in T1-T2? *Nvm read more and its more clear that the splinters occur for future rather then the past/present.. right?"*
The splinters alter what happens AFTER the time travel event, but each time travel event itself appears to arrive in the timeline, regardless of whether or not it directly ties into the upcoming future (because it's already a part of the established past). Genisys seems to show that - because of this mechanic - even time traveling an entity back BEFORE the other time-travel events can't effect them, because it's a part of the established history that can't be altered. (There's no way to time-travel anything into the Timeline 1, 1997-based Judgement Day and kill that Kyle Reese before he leaves, because he's not from the upcoming version of the future anymore, and there's no access to that timeline, so he ALWAYS arrives).
This is why, regardless of the fact that Sarah's paren't get killed, everyone from the various older Judgement Day timelines still show up exactly when is expected, even if the events that they're sent there for aren't. Kyle still shows up, even though Sarah isn't who he expected. This almost certainly means that even if John Connor isn't born, a T-800 & T-1000 will still be showing up and looking for him. This is because they're from Timeline 2, and are intersecting the correct moment in the (now most recent) altered timeline.
I kinda like this idea and it also helps me to take in something that always nagged me about Salvation. In T3 its established that Skynet was a government botnet gone self aware yet in Salvation it felt like Skynet was back to being an independent company like Cyberdyne with the way they reached out to Marcus. I havent seen either T3 or Salvation in awhile but from memory it really did feel like these 2 skynets were 2 completely different entities operating in our present time.
*Disclaimer I havent watched TSCC so idk if that adds anything to the different feeling skynets in T3 and T4*
It's been a while, but I know that T4's Skynet is very much a calculated entity which seems to be disparate from how it's portrayed in T3 (this bothered me as well), but I assumed that this would be from it gathering data about itself. The director of T4 (McG) had really good mechanics for how Skynet operated, and was why I liked the film as much as I do.
It's been several years since I watched TSCC, but the most important thing that it dealt with was Skynet learning from things over each timeline, and also the fact that the T-1000 units weren't really under Skynet's complete control, because they were overly autonomous (hence why the T-X was based on a more reliable unit, and just used the mimetic poly-alloy as an external covering).
Right now, my biggest questions are: Which type of Terminator killed Sarah's Parents (was it the T-1000 that they're fighting in the '80s)? And most importantly, who the fuck is Matt Smith's character, because he exists in the future and is CLEARLY an important reveal, since they're not giving his name, or any other details about him at all - he wasn't even shown in the trailer.
Yeah, regardless of what "The Sarah Connor Chronicles" (completely separate from the film continuity) and McG (about as credible to the franchise as I am after the movie he made) have to say about it, I'm not yet convinced the fundamental plot element of the entire concept has been thrown out the window for no good reason.
Near as I can tell at the moment, things appear to be happening the way you think they are because this is the first time Skynet got the wacky idea to send an assassin back to an earlier time rather than a progressively later one. All the other travelers may still be showing up because of some wacky mechanic of time travel.
In any case, even if they are going for the alternate timelines idea, by your own words, they're still overwriting things and eliminating those timelines by doing shit like fucking with the events surrounding the assassins who were sent back previously -- so there wouldn't be a T2 alternate timeline if the very same T-800 who was sent back in the first film now didn't do any of the things that created the T2 timeline.
Again, not convinced this alternate universe idea is anything more than a terrible, inapplicable idea from TSCC and a drunken ramble from McG. I may yet be proven wrong. If so, that's fine. Franchise will officially be garbage at that point anyway.
Yeah, regardless of what "The Sarah Connor Chronicles" (completely separate from the film continuity) and McG (about as credible to the franchise as I am after the movie he made) have to say about it, I'm not yet convinced the fundamental plot element of the entire concept has been thrown out the window for no good reason.
Near as I can tell at the moment, things appear to be happening the way you think they are because this is the first time Skynet got the wacky idea to send an assassin back to an earlier time rather than a progressively later one. All the other travelers may still be showing up because of some wacky mechanic of time travel.
In any case, even if they are going for the alternate timelines idea, by your own words, they're still overwriting things and eliminating those timelines by doing shit like fucking with the events surrounding the assassins who were sent back previously -- so there wouldn't be a T2 alternate timeline if the very same T-800 who was sent back in the first film now didn't do any of the things that created the T2 timeline.
...I thought I explained that pretty clearly, and I most certainly did not say that timelines were being eliminated or overwritten. I sketched it out a little diagram because of reasons, though. (Apologies about my shit handwriting).
Essentially, Terminator doesn't allow for you to go in and prevent any of the time travel that's happened, because the timelines that they come from get splintered off and the changes all cascade into the new timeline. As soon as Terminator 2 changed events to alter Judgement Day, that became the way that time travel functionality was established. If J-Day got changed, and the timeline was self-correcting or a single contained loop (like T1 insinuated by having John Connor exist as a bootstrap paradox), then changing or preventing J-Day would've generated a paradox by preventing that Kyle Reese from coming back in time. Because that wasn't the case - the future that was was created in Terminator 1 that lead to Terminator 2 isn't the same future that Kyle Reese from T1 experienced, so it created a new timeline, but didn't overwrite the previous one -- you're dealing with a new/alternate timeline. T3 further proves that with the TX & T-850 being sent back from a completely different apocalyptic future. It's not just TSCC & Salvation. It's literally part of how every film from T2 onwards is set up in order to function.
Again, this is just like saying that the crew of the Enterprise can't travel back in time in the current Star Trek IX timeline to prevent Old Spock from arriving, and at the same time, old Spock arriving in Star Trek IX doesn't undo or overwrite anything from the timeline that he came from. Even if you time traveled back into the Star Trek IX timeline and shot Kirk & Spock in the face before they became a part of the crew of the Enterprise, Old Spock would still show up, because he's from the original timeline and you've done nothing that's interrupted that.
Again, not convinced this alternate universe idea is anything more than a terrible, inapplicable idea from TSCC and a drunken ramble from McG. I may yet be proven wrong. If so, that's fine. Franchise will officially be garbage at that point anyway.
By "fundamental plot element of the entire concept," I'm referring to the accepted notion from the first three films that changes to the past would affect the present/future. The idea is literally never contested even once, even in the face of what looked like a time loop at the end of the first film.
If the original timeline (where Skynet went live in 1997) is still out there, then the human resistance won a long time ago and Skynet's efforts have been increasingly fruitless.
Anyway, you're saying that the T-800
Arnold kills in the trailer
is literally the same T-800 (not a copy created as a result of splintering) from the first film. That's what you wrote in that long post up there.
If the Kyle Reese who arrives is literally the same Kyle Reese and the T-800 is literally the same as well, then the events creating the T2 timeline simply will not happen because of the events that now take place in the 60s and thereafter (Sarah's parents being murdered, her being raised by yet another T-800, etc.).
You're arguing for two contradictory styles of time travel simultaneously. You're arguing for a splinter effect, but saying all time travelers will still arrive in the same universe regardless of time travel to years before or after the target year -- which is simply at odds with how the splinter theory of time travel works. The splinter theory demands that any act of time travel immediately creates a new universe with "copies" of everyone and everything.
If the same Kyle Reese and T-800 who were in "The Terminator" show up in an altered (rather than alternate) 1984, where they play out a new set of events rather than simply repeat what happened in "The Terminator," then you aren't dealing with the splinter theory of time travel anymore. You're talking the overwrite theory.
Now, it's entirely possible the filmmakers are planning to mesh the two in a way that would never make sense, but for now, I'm going to assume that they want their story to be coherent and will be sticking with one or the other.
By "fundamental plot element of the entire concept," I'm referring to the accepted notion from the first three films that changes to the past would affect the present/future. The idea is literally never contested even once, even in the face of what looked like a time loop at the end of the first film.
Still isn't. I've specifically mentioned that each timeline gets created because of the changes that they made altering the previously established events of the original Judgement Day.
If the original timeline (where Skynet went live in 1997) is still out there, then the human resistance won a long time ago and Skynet's efforts have been increasingly fruitless.
The human Resistance DID win in against Skynet in that timeline because of John Connor (technically speaking) a long time ago. Skynet's final move was going back and killing John Connor, so that in the up-and-coming altered future, Skynet would be victorious.
Every time that Skynet sends something back, there's a smaller possibility of humanity being victorious on that new timeline's up-and-coming Judgement Day. The important thing is that Skynet is always the one making the time travel move. Because it's always the Resistance chasing Skynet, Skynet's technically lost every time that time travel takes place. The difference is that (as is shown in Salvation), Skynet keeps adapting its tactics and getting closer to victory every time.
The key here is that Skynet only needs to win ONCE, and then, if it doesn't send anything back in time, that is the only timeline and it's victorious. Essentially the whole Judgement Day scenario ends in one side's victory when you can prevent the opponent in the latest timeline from sending something back.
If the Kyle Reese who arrives is literally the same Kyle Reese and the T-800 is literally the same as well, then the events creating the T2 timeline simply will not happen because of the events that now take place in the 60s and thereafter (Sarah's parents being murdered, her being raised by yet another T-800, etc.).
The T2 timeline can't be prevented by killing that T-800 now, because that timeline already exists as a part of the current timeline. That little zig-zagged line gets compiled together into the new timeline (because it's combining the time travel from multiple different timelines). That bottom bit is the timeline that the "pops" Terminator comes from - that's why they already know about everyone that's going to be sent back, because they happened in versions of Judgement Day that became concretely established once the time travelers arrived.
The { bracket I have at the bottom shows that the exact events in T1-T3 are the established timeline events for the cinematic universe. The Triangle, Circle, & Square show where the time travelers enter from their own unique timelines. They're all coming from futures that already happened, not the new one that they're approaching, so those old timelines are splintered off - they CAN NOT be overwritten.
You're arguing for two contradictory styles of time travel simultaneously. You're arguing for a splinter effect, but saying all time travelers will still arrive in the same universe regardless of time travel to years before or after the target year -- which is simply at odds with how the splinter theory of time travel works. The splinter theory demands that any act of time travel immediately creates a new universe with "copies" of everyone and everything.
The time travelers still arrive in the latest timeline regardless, because they're an established part of the PAST from the timeline that the NEWEST traveller is from. You can think of all the time travelers in the latest timeline as "copies" (since Technically T1 has a "Timeline 1" Kyle Reese who arrives in the '80s, as does The T1-T2 timeline (2), T1-T3 timeline (3), & T1-T4 timeline(4), etc.) but for all intents and purposes, from the point of view of the Kyle Reese who arrives in Timeline 4, he's still the original.
Because the past that lead to the "pops" Model-101 contains the events of the T1-T4 films, they'll be encountering the Timeline 1 Kyle & T-800, Timeline 2 T-800 & T-1000, Timeline 3 T-850 & T-X, because of them being a part of the past that they CAME FROM, even if it's no longer a part of the future that they're CREATING.
(related, I assume that they won't get along with the T2 T-800 if they're doing what it looks like, and haven't had a kid named John Connor, they're technically working against its primary objective).
If the same Kyle Reese and T-800 who were in "The Terminator" show up in an altered (rather than alternate) 1984, where they play out a new set of events rather than simply repeat what happened in "The Terminator," then you aren't dealing with the splinter theory of time travel anymore. You're talking the overwrite theory.
IF that happened, yes... but I'm not at all stating that that is the case at any point in what I've said -- and this seems to be the major point that you're massively misunderstanding and completely misconstruing everything from.
You can follow the Timeline 1 Kyle Reese into any of the later timelines, and he's still the "original" one as soon as he arrives there for all intents and purposes, because he's a part of a timeline that was already built with his arrival having been established in a way that it can't be prevented. They're all copies in that they're from the latest splintered timeline and not the VERY first iteration of time travel, but at the same time, they're also no more or less original just for which iteration of the timeline that they land in. He's still the Timeline 1 1997-J-Day Kyle Reese any way you slice it.
So...if every timeline sent Kyle Reese back in time to 1984, would that mean you would end up with three or four different Kyles popping up at the same time, all from different futures?
So...if every timeline sent Kyle Reese back in time to 1984, would that mean you would end up with three or four different Kyles popping up at the same time, all from different futures?
If every timeline had done that, yeah - but that doesn't happen because each timeline only ever sends back one Resistance member, and one Skynet unit.
Then again, if each timeline was sending back its own Kyle Reese (and then the other new folks), we'd be dealing with an overwriting timeline, rather than a cascading one, so that still wouldn't happen.
But yeah, this is one of the main reasons that I really hope that they keep with the same version of time travel that they've been using thus far, because it's easy to fuck things up. (Related, the original post that I linked to with all the timeline explanation was done about a month before the TSCC episode that had Derek & Jesse confirm that the different timelines happen, and well before Salvation, so every iteration thus far has been consistent with the time travel, so fingers crossed).
I know that's an old diagram, but TSCC doesn't coexist with the T4 timeline. It branches off the T2 timeline before T3 happens due to Cameron's arrival. (The cyborg not the director.) But I'd just as soon leave it the way it is, because dear lord an accurate TSCC picture would turn that diagram black.
"Thus far" apparently being "an interview about that one movie that was universally panned and everyone's ignoring"?
I still say everything (that matters) points to things being best imagined as an x-y graph where time moves forward as you move from left to right (the x-axis), but evolves with each new interference in the past, here visualized as moving up a tick on the y-axis. This ever continuing evolution of the timeline then becomes best demonstrated by the diagonal line that could be drawn, moving ever to the right and upward as time continues moving forward and as the timeline continues evolving/being overwritten.
So, the events of the original timeline, for instance, still happened, but somewhere in the bottom-left of this graph. That timeline doesn't keep moving to the right along the x-axis, though. This timeline evolves into the T1 timeline, and the graph moves both a tick up and a tick right -- so, diagonally. This then happens again via the events of T2, and once again via the events of T3.
Those previous timelines didn't now "not happen," but they're not still floating around out there separately either. They evolved into the eventual T4 timeline. In this way, the original timeline, the T1 timeline, the T2 timeline and the T3 timeline are all technically part of the past of the T4 timeline, which is now the only one moving along the x-axis (at least until whatever happens in T5).
And, hell, all that still leaves Skynet the ability to learn from its past efforts in the aborted futures because its failed assassinations are all part of the established past that evolved into the T4 timeline. They don't need a magic window on other universes, or whatever the hell McG was imagining.
The notion of the original timeline, the post-Judgment Day T1 timeline, and the post-Judgment Day T2 timeline all still existing as separate places one could conceivably go visit just doesn't ring true with what happened in these movies.
I know that's an old diagram, but TSCC doesn't coexist with the T4 timeline. It branches off the T2 timeline before T3 happens due to Cameron's arrival. (The cyborg not the director.) But I'd just as soon leave it the way it is, because dear lord an accurate TSCC picture would turn that diagram black.
Yeah, it certainly doesn't coexist with the T4 timeline. It could've happened after T3 if they'd jumped the events in 2004, and then run into the T-X roaming around for a few years when they arrived in 2007 (like what appears to be happening in T4), but there's just a lot of crazy cool stuff that never came through with that series (and I think that they wanted to ignore T3, and focus more energy on the rogue T-1000's).
I still say everything (that matters) points to things being best imagined as an x-y graph where time moves forward as you move from left to right (the x-axis), but evolves with each new interference in the past, here visualized as moving up a tick on the y-axis. This ever continuing evolution of the timeline then becomes best demonstrated by the diagonal line that could be drawn, moving ever to the right and upward as time continues moving forward and as the timeline continues evolving/being overwritten.
So, the events of the original timeline, for instance, still happened, but somewhere in the bottom-left of this graph. That timeline doesn't keep moving to the right along the x-axis, though. This timeline evolves into the T1 timeline, and the graph moves both a tick up and a tick right -- so, diagonally. This then happens again via the events of T2, and once again via the events of T3.
Those previous timelines didn't now "not happen," but they're not still floating around out there separately either. They evolved into the eventual T4 timeline. In this way, the original timeline, the T1 timeline, the T2 timeline and the T3 timeline are all technically part of the past of the T4 timeline, which is now the only one moving along the x-axis (at least until whatever happens in T5).
Right. Still what I drew, with the exception that - while you could say that the timelines are still "floating out there" they're totally unreachable. They're part of a past that was derived from a version of a post-apocalyptic future that's been altered/averted and thus can no longer be accessed through time travel.
To use some Doctor Who terminology, each new Timeline that's created with any of your X-to-Y-Axis diagonals is also a Timestream of all of the events that came before it (because it's a timeline that involves time-travel in its past - i.e. the new Model-101's past involves events post 2004, despite the fact that he's now in the 1980's). The thing with Timestreams is that, once established, you can't loop back into a different reality from the one you're in no matter which one you came from, so it doesn't really matter whether those old timelines technically still chug along without you, or if they disappeared into the ether the moment you left them - they're not overwritten, and they're inaccessible either way (because they're on a different Y-coordinate as you put it).
And, hell, all that still leaves Skynet the ability to learn from its past efforts in the aborted futures because its failed assassinations are all part of the established past that evolved into the T4 timeline. They don't need a magic window on other universes, or whatever the hell McG was imagining.
But that's just it. What you described right there IS EXACTLY what McG was talking about with Skynet keeping track of and being aware of the previous/alternate universes and how those attempts failed, and then building off of them, as I've also been describing this whole time. xDDD
The notion of the original timeline, the post-Judgment Day T1 timeline, and the post-Judgment Day T2 timeline all still existing as separate places one could conceivably go visit just doesn't ring true with what happened in these movies.
I've said multiple times that all of those previous timelines are left inaccessible, and there's no way to go back to them, and I don't think anyone else's suggested otherwise either.
tl;dr - I'm pretty sure that Tres & I actually agree completely about how this all works, but we just haven't realized it yet.
It sounds like it. What you call "branching timestreams" must be what I'm calling "overwriting." I think of branching as the kind of time travel we see in Marvel's comics. =P