One US top ten album, only one single that charted in the US and small venue tours. Are you the guy that usually claims Aaron Carter has a megastar career too?
David is still successful and still sells out venues when he tours there is a reason why he sells out and still makes enough money to produce his music, he has his specific target audience and he truly acknowledges that as far as indie artists go he's doing quite well. He's not in any means as relevant as he once was but he is doing well enough to be happy and I think that matters most than being a chart topper