I may be wrong, but it feels to me that SE is quite ignorant of the fandom, and doesn't realise Tifa and CT's popularity, even though she trusts the top charts ahead of Aerith for years now. Some of their PR has been really questionable, and can only be understood as "Aerith is our golden child, everyone must see her like that".
Yet, they do know that Tifa sells - they priced her figurines higher than the others, and they still sold faster than the others at a con last week... yes it was an SE event. But it doesn't seem that they've grasped how much she is loved for herself and not for weird otakus. They're still in a very 90's mentality regarding Aerith and Tifa PR-wise, and that just pisses off people. Tifa fans crave Tifa merch so much that they buy literally anything with her, which means SE doesn't put any real effort on her, meanwhile Aerith gets all the goodies a year before Tifa does.
And all of that for pretty poor quality merchandising-wise, because honestly all of SE's merch is quite the rip off, IMHO.