Well, there is that whole talent thing too. While being Conversant in a medium certainly helps... there will always be those that will inherently be able to do things others cannot. With half the effort. I think one of the tricks of any medium is finding a particular strength and utilizing the hell out of that. Of course one should never become too comfortable, that just leads to hackwork. It's nice to have your own particular area where you can shine, though.

Man, that fresco botch is AWFUL! That's just moronic hubris.