An article at AVClub talks about bands that were once good and then not so good, but Buzz Osborne makes a point that I think applies to artists generally:
You don’t have to keep doing [art about teen angst]. You just have to realize that what you were doing was good. I got the feeling that they didn’t think that it was any good. There’s no more of that anymore. Even with Metallica, their albums still sound like there’s some sort of edge to them; it’s not just bad R.E.M. again, you know what I mean? To me, R.E.M. sounds like a metal band compared to where The Replacements ended up. They gutted everything that was good about them.
Take Tom Waits. His newest album is one of his best albums ever. He hasn’t forgotten what was good about him; he’s just improved upon it. You can tell he’s Tom Waits, because it sounds like Tom Waits and everything he ever did. But it’s an improvement, it’s a step forward, and he managed to do that.
That’s up to them to do that. If you want to gut your sound in order to sell millions of records, good luck with that. Hopefully it’ll work out for you and if it doesn’t work out, then that’s the saddest story of all. There’s nothing sadder than a band selling out and having it not work.