Student vs Filmmaker

Reading through Cassavetes on Cassavetes and thought this was interesting...

There's a distinct line between being a student and being a filmmaker that I don't understand and I don't see. I know that every filmmaker that I know personally, from Don Siegel to anybody - to anybody! - is still beset by the same problems on every single film, including how to overcome the commercial aspects of the film. And as you get older you make more complicated films. When you're young you make very simple films, and they're probably better. But as you get older those complications make you sell out much easier. Not your age, or you standing, or your money, or anything else, but the fact that you really don't have any ideas that aren't commercial. You really don't. - John Cassavetes