>>106552725>The bubble won't burst but are there signs of the air slowly seeping out?
Nope. Captain Marvel is making great money. The only movie I think that did even vaguely not great is Ant-Man and the Wasp. And it's not likely that was meant to be anything special.
Aquaman and Venom have also done very well, so in general Superhero movies continue to make the big bucks. Disappointments are relative to the overall spectacular profits of the Superhero movie industry, not any actual sign of air seeping out.