Original movie scripts almost extinct?

As many of you might have noticed more and more movies are based on pre-existing material instead of original scripts. Books, comics, cartoons, tv series, even videogames are turned into movies.If you see some of the box office hits of the last decade, you will see that the majority of them are adaptations. Lord of the Rings, Harry Potter, Twilight, the Bond movies, The Dark Knight etc. Some of the few exceptions I could think of right now are Avatar and 2012. As it seems, nowdays most books are created with the potential to become movies. Is there no imagination left to the script makers? What do you think?
Posted by baker1skter

w@ComicMan24: well what you all said was true. but the writers have to bring the movie to life through the script, bad writing=bad movie. I think its harder to script an original movie then one in another medium because the idea is already there.

Posted by ComicMan24
I agree with what you said. Of course it's easier.
Edited by Tomokata

Not only is it easier, they go where the money is. 
Resident Evil games made a lot of money!  Cash in on that!  Same goes for comic books and novels.  
It's not about releasing good quality entertainment anymore, it's about show me the money. 
Edit for shameless plug:  Which is why you should support your local independent film community!