why marvel hates stucky? because Captain America is (should be) a man
let's be real. Marvel isn't erasing stucky, they are merely erasing Bucky from Steve's storyline, not the other way around, they even went so far as to canonly admitting that Steve's Bucky's homecoming. why can they tolerate a possibly queer Bucky but not Steve? because to them, Steve Rogers is Captain America and Captain America is this white, straight, masculine national hero who embodies the traditional male fantasy. Bucky is just a sidekick that no one gives a fuck about while Sam is never gonna be the real Cap. bucky is the 'other' and by nature he is not important, he is put in a inferior position and his femininity (being queer) is slightly more acceptable than steve's.
what's funny is that, only Bucky saw Steve Rogers when the whole damn world sees Captain America. Bucky Barnes is the one that makes Steve Steve, as long as Bucky exists Steve can't be the hypermasculine icon Marvel wants him to be. why? bc it's in the fucking narrative. in this sense, Bucky Barnes is the only thing that stands in between Steve and the erroneous reading and presentation of Steve's character. So, he has to be removed.
and I'll expand that on the stomper or whatever knockoff ironman suit they put him in in WhatIf
there's a wonderful meta about why Steve is a feminine character. his masculinity isn't born but made and he was objectified and ridiculed for it. that artificial masculinity gave him the feminine experience and that's what makes him fascinating as an ostensibly hypermasculine hero. this dichotomy between Steve and Captain America created by that body is one of many reasons why Steve ≠ Captain America. by putting him in that suit, they are emulating masculinity with a giant piece of metal and tech that has phallic analogies written all over.
and that makes Steve, what? a knockoff tony stark? bc tony at least designed the thing. Steve is just a dude borrowing it. there's no depth and certainly no positive gendered reading came out of it. he becomes this simplistic male hero fantasy (like ironman). then, Marvel swapped Steve and Bucky's storylines but lost all the nuances because bucky is also heavily female-coded, especially his suffering as the winter soldier. the cartoon has none of that.
marvel is entirely ignorant as to why the Cap trilogy the best Marvel movies and steve&bucky the best characters, and they wonder now why steggy isn't well received. erasing Bucky from Steve's plot just makes the character boring. stucky isn't popular (entirely) bc they were played by cute white guys. it's bc their relationship adds depth, GENDERED DEPTH, to them and that's relatable to all the women that made the fandom so goddanm influential. Steve Rogers isn't your white male fantasy no matter how hard you try.