I don't think Black Panther would have happened without years/decades of less 'encumbered' art and philosophy and activism behind it. Disney is not the vanguard of change. But they are one of the cultural gatekeepers of mainstream acceptance. Whether or not that's a good thing is a separate conversation. Controlling for the fact that they are, their backing behind the movie and the message is super important because of the mainstream legitimacy that comes with it. An arthouse movie with this message may be able to be even bolder. But its reach would likely be tiny. This is a massive movie with incredible reach that plants a flag for representation in the most culturally significant (in terms of reach) film genre out there right now. Again, you can bemoan that superhero tent poles occupy that position, but that's a separate conversation. They do, and so this matters.

There will eventually be an openly gay superhero who interacts with a gay partner in a blockbuster movie. And that will matter not because it will be subversive. It will matter because its representation in a film like that sends the signal that being gay is no longer, in itself, something that needs to be thought of as subversive. It will have reached that point on the back of more interesting and challenging works of art that helped move the needle, but that film itself will be able to take the victory lap.