The "hobbyists rule" argument is somewhat chimerical.
Absolutely nothing about contemporary copyright laws prevents amateurs from producing as much work as they like. The only thing they can't do is make derivative works without permission.
Within those confines, derivative works like fanfics are often tolerated, as long as the fan-author does not try to charge for the work. Even Rowling, who has meted out numerous IP-based lawsuits, has given tacit approval to fanfics (
http://www.prweb.com/releases/2008/07/prweb1080574.htm0)
So, other than actually selling fanfics, there is no reason why amateurs can't do as much work as they want right now. Yet somehow, most of the art that people buy is still professionally produced. Go figure....