I don't think movies based off existing material is what is going to burst the bubble, because there have been movies based off of books and other such things since they've been making movies.
If the bubble burst, it will be because there are too many movies connected to each other, and assuming DC's ho-hum attempt so far at jump starting their own cinematic universe, if the connected movies turn out like Green-Lantern, that could start to sour the Connected Movie thing. Just like Fox is going to try and push The Fantasitc Four into the X-verse, and Sony is expanding Spiderman into a yearly franchise.
It also really doesn't help that Marvel is about to have 5 different connected shows + a miniseries (6 if you count Agent Carter) in addition to all the movies to follow, and that may become just too much for most causal followers to ingest, especially if they all become intertwined to to point where you have to watch some of everything to understand all of anything.