The comic book movies and movies of that ilk are the reason why Hollywood stagnates. Spielberg and Lucas believe that these type of movies will eventually shutdown Hollywood altogether in a chain reaction when the "Blockbusters" fail.
http://variety.com/2013/digital/news/lucas-spielberg-on-future-of-entertainment-1200496241/
“They’re going for the gold,” said Lucas of the studios. “But that isn’t going to work forever. And as a result they’re getting narrower and narrower in their focus. People are going to get tired of it. They’re not going to know how to do anything else.”
“There’s eventually going to be a big meltdown,” Spielberg said. “There’s going to be an implosion where three or four or maybe even a half-dozen of these mega-budgeted movies go crashing into the ground and that’s going to change the paradigm again.”
Lucas predicted that after that meltdown, “You’re going to end up with fewer theaters, bigger theaters with a lot of nice things. Going to the movies will cost 50 bucks or 100 or 150 bucks, like what Broadway costs today, or a football game. It’ll be an expensive thing. … (The movies) will sit in the theaters for a year, like a Broadway show does. That will be called the ‘movie’ business.”
Ah, see they mine the well known comic books. Not Elephantmen, Not Elfquest, not Fables (which is very unique take on the Fables of yore), Grendel, not focusing on villains like Venom, Carnage, Deathstroke...
And they need to stop effing around with the Parker series.
Then you have various literary works that can be made into movies. For instance
On A Pale Horse, and that series.
Historical figures like Marcus Garvey and Swamp Fox (Disney had a series, but to date I don't think that there has been a big studio backing a movie).
Keep in mind, Spielberg has Falling Skies going for 3 seasons, he had a thing about Aliens, and had a prime time (from what I remember) cartoon about Aliens, and hybrids.
Lucas? The whole Star Wars genre is based on Medival Knights, etc.