I’m not sure the flagging of viewer numbers for super heroes is indicative of people suddenly having better taste or any understanding of the finer points of cinema production.
They’re just burnt out. A glass of water is great if you’re thirsty, but if you’re in the middle of one of the great lakes… Well, too much of a “good” thing. Not that super hero movies were ever good, but they were entertaining for their time. That time seems to have passed by the general public, and Hollywood can’t keep up. Then throw AI becoming a thing to the general public, combined with writers (and now actors) striking and you’ve got a recipe for drek.
That being said, their collective bargaining is inspiring to a regard, and depressing in others.
Unions and strikes work, from a historical point of view. They were just beaten out of Americans and now it seems only the elite and their porcine protectors have access to unions.