Is it, really? Most dating games start from an assumption that it's the MC that needs to pursue the eligible ladies (and dudes where applicable) by earning their approval with MC's interest taken as a given and that's the mold the devs were leaning on to leverage your assumptions from.
As Rose Alive helpfully demonstrated, even in non-dating games with romance elements, it's the companion's opinions you're swaying, not the main character.
I stand by my analogy that the affection mechanic is in essence a great big shell game, there to keep you slightly off balance and to set you up for the rug pull moments later in the game.
I don't think you're correct there. I don't think that in dating games that the MC's interest is a given. Sometimes it's a given FOR the girl you are pursuing, yes, but not for the other candidates and since all candidates start at the same location naturally the MC is assumed to not be in love with any of them at the start. There there is often a clear arc where they slowly fall in love with the person, the only true given is that THE PLAYER wants the main character to be interested in the girl they are pursuing.
But usually the point is that the actions you as a player choose show romantic interest in a particular girl, making it seem like "a given", but like Yumelinh said it's really our choices that push our character in a certain direction.
FFVII is a little more complicated. In case of FFVII, Cloud is in love with Tifa, that is a given, because regardless of the future, the past doesn't change, and the past is that Cloud is in love with Tifa. Aerith meanwhile is in love with Zack for the same reason. This means that there are already a bunch of dynamics rather than starting from zero. Cloud already loves Tifa, so courting her shouldn't change that, but it might make him more comfortable around her which changes their relationship. Tifa already has a crush on Cloud but probably has further to grow and since she's not braindamaged any assertive actions would have to come from her. Meaning that her state of mind is most important for her relationship with Cloud, Tifa essentially could have Cloud any time she wants as long as she goes for it.
For Aerith it's different, she'd need to both fall in love with Cloud over Zack, but also switch Cloud from loving Tifa to loving her before she would even be able to make a move. So from a gameplay perspective that's more akin to the traditional romance game where both characters need to reach a certain point I'd say, but since Cloud already loves Tifa I can't say that him acting favorably towards Aerith would reflect his "given affection" for Aerith. I think it would just be Cloud doing stuff, Aerith growing fond of him, and those interactions then retroactively making him grow more fond of her. It's also complicated ofcourse by us not knowing to what degree Cloud is aware of his feelings for Tifa.