In a recent interview Steven Spielberg had the following to say about the current flood of super hero themed movies we have been seeing:
“We were around when the western died, and there will be a time when the superhero movie goes the way of the western. It doesn’t mean there won’t be another occasion where the western comes back and the superhero movie someday returns. Of course, right now the superhero movie is alive and thriving. I’m only saying that these cycles have a finite time in popular culture.”
Ironically though he has no leg to stand on, considering he and Lucas ushered in the age of the summer studio blockbuster’s with movies like Jaws and Star Wars. Part of the reason the western died was that the landscape of the world changed. People were less interested in seeing tales set in the past and wanted to see more set in the modern or future times.
Since a superhero film can be set in anytime I don’t think the genre will die as much as it will change.