I never read comics when I was a kid.(well, thats not true, I read Heavy Metal)
I read sci-fi(Niven, Asimov, Bradbury, etc) and fantasy(Tolkien, Lovecraft, Howard, etc).
I don't get this thing with comics. Most of the comic book based films are ok at best...
Are they really going to make that many comic book based films?
That is just sad.
There are so many good sci-fi and fantasy books/stories out there.
It would be nice if something not ending in "man" was made into a film.
I think there's two factors. First successful comics consist of a long running series. Even the best science fictions stories are pretty niche on a society level, how many people have actually read Caves of Steel or Ringworld?
But as for comics, even someone like myself who never read a comic book is familiar with every character listen there besides Shazam and Cyborg. Every comic movie already has a huge potential audience already familiar with and sympathetic to the source material, it's hard for books to match that.
The second factor has to do with the nature of the form.
A great book for adults requires compelling ideas, these are generally communicated through dialogue and introspection.
A movie has to communicate ideas though visuals and emotion, to make a great adult book into a movie you have to strip out what made it great and try to communicate that in a completely new manner, it's possible (2001: A Space Odyssey) but it's hard. Asimov was mostly discussing ideas and dialogue, do you really think that will translate into a great movie?
It's no mistake that almost all the successful science fiction book adaptions have been from the young adult market. Young adult fiction requires a lot of action and easy philosophy to keep the interest up, the exact same formula that creates a smart action film.
Comics on the other hand are a visual medium already, they're written to communicate using similar amounts of dialogue and action, movies are even filmed with the aid of story boards that aren't much different from a comic. To translate a great comic into a great movie is mostly just a task of translating the style.