It’s cyclical. Sooner or later a generation of movie goers will look at the superhero genre and go “ew. My father likes those kind of silly movies” or “ew. This is so dumb, give me something more countercultural” and flock to something else. Studios will respond after stumbling for a bit.

You can see it with musicals, then cowboy movies, then 80s action movies. Eventually the younger audiences won’t be want what came before.