Can't say I agree with this entirely. I absolutely agree that going to college for four years will not make you into a good artist. But "being born with it" will not make you a good artist either.
Hammering away at it two hours a day from age 12 to 22 will make you a good artist. You may never be a great one (that is where being born with it comes in). But you will be a good one. And the same is true for most pursuits.
There was a great forum post a while ago where some guy could barely put together a stick figure and three years later (after an hour a day, every day) he was making oil paintings that people would actually pay for. I can't remember where though. Anyway, that sort of thing has nothing to do with talent. It's hard work and sticking to it.