Yes. When an artist tends to get big, the music gets dumbed down. Musicians don't bother putting any time into their work after they start getting big checks, because it's no longer the music that sells the albums, it's the marketing. That's why people so often complain about musicians selling out because they turn to crap. This applies to any genre of music. When you're a struggling musician with absolutely no presence on the scene the only way to gain exposure is to use every ounce of talent and skill you possess to get attention. After you have an installed fanbase, there's no reason to put so much effort into your work, so you can just lay back and watch the cash roll in.