NONE of those theories are the reason. And frankly, I find it worrisome none of these guys can even come close. Studying methods becoming more efficient? C'mon, dude.

There's a great scene in the movie Orange County (Colin Hanks, Jack Black, others) where the main character, a high school senior, is arguing with his mother, who's worried about the prospect of him leaving home. Shaun: "But I have to go to college." His mother: "Why?!" Shaun: "BECAUSE THAT'S WHAT YOU DO AFTER HIGH SCHOOL."

These days, most of us are not going to college to learn anything. We're going because that's what you do after high school.