There's Jonathan Coulton, who at one point was pulling in $500,000/yr... and there's uh...
Erm...
Oh, look! I'm needed in the basement!
Erm...
Oh, look! I'm needed in the basement!
Not to take away from the quality of his music, which is really good (I have a few on my playlists), but there were also plenty of other very good musicians that tried thing-a-week and didn't break through.