In regards to Escapism, it is no coincidence that Harry Potter and The Lord of the Rings gained the attention they did right after 9/11 and the beginnings of the War on Terror.
I see the Superhero movies in a couple of ways:
-They are a step back into reality from where we were with the whole fantasy realm. Following this line of thinking, it is interesting to note that The Watchmen is finally coming out because that is basically about the death of superheroes or at least the death of confidence in superheroes.
-Technologically speaking, the reason they are all coming out now is because Stan Lee and Marvel were smart enough to wait for the industry to catch up with the vision. Most Marvel movies would look pretty cheesy with the graphics of ten years ago, so they purposely held off until the time was right.