So changing their sound, being innovative is a bad thing? I thought being innovative was always positive!
On a more serious note, I feel for bands that have people that latch on to a specific song or even album. Sometimes you simply can't catch lightning in a bottle again. On the other hand, there have been bands that I enjoyed in the past that became "uncool" simply because they had a song used in a movie or similar.
Some people value being, or at least appearing to be, unique and different more than what band they listen to or products they buy.