Have been watching kids grow up into these things the last couple of years. I think it's mostly disillusionment, pampering parents, or just out and out laziness. I know a guy in my grade (17 years) whose mom still picks out his clothes every day. I also know a lot who either don't think they're smart enough or that there's no point in trying. Then of course there are the lazy assholes who can't be bothered to do anything but smoke pot and play video games or mess around on Facebook.
Anyway, I'm still a kid, more or less, so I don't have exactly the distance to get a clear perspective. This is just what I've noticed.