I've been self-published for five years and haven't earned a dime, but I have heard success stories of self-published authors. A friend of mine self-published his comic books on my suggestion and from what he told me, they became pretty successful.
Realistically, it all depends on how much work you're willing to put into marketing and such.
I finally got tired of attempting to do all the legwork by myself and simply use the self-published books for copyright protection. If someone buys it, fine, but I don't do much with them anymore. Instead, I almost accidentally got into publisher hunting last year. I wrote about it in several hubs and included one recently explaining a specific clause to look for in publisher contracts.
I'm not saying a publisher is better than self-publishing, but in defense of both, there's a lot of work to be had. Some publishers still make you do all the marketing and such yourself.
So the real question would be, how hard are you willing to work for success?