The problem I have is a bias I still harbour, though I'm trying to get rid of it, is that alot of self-pubbed books just aren't as well edited or as interesting beyond being ridiculously fast paced books. There's so many thousands of them that finding really good ones is rare for me. I don't think I've bought a self-pubbed book in over a year, and the fact that I can go to waterstones and pick something there is something you just can't do self-publishing wise, especially if you don't want to work with the capitalist machine that is Amazon more than is necessary!
Though, publishing just to hope to make a million in sales is a bit extreme, too. The bestseller lists are questionable at the best of times and it's the same in almost every artform -- see Kanye's recent rants on his music contracts over on twitter, for some equally brutal contracts!