Why are kids reading levels so incredibly low today?

At my high school I see many freshman and sopres even juniors and seniors reading Twilight, Percy Jackson, and other weak young adult novels.I've read Twilight and Percy Jackson and they're written poorly even for a young adult novel. I think an 18 year old reading Twilight is disturbing and scary is my generation really this stupid? I read stuff like The Scarlet Letter, Catch 22 and Brave New World. I mean we can't deny that my generation is dumb. I'm not trying to sound mean or critical,but honestly if you're a freshman you should be able to read above that level by now. What can we blame this on? I apologize if I offend anyone.