Anyway, I'm fine if a band experiments because they want to try something different or whatever; I might not like it, but I won't really hold it against them....
On the other hand, if a band makes an obvious cash grab, and fails, they do lose some points in my book. I think it does show a lack of commitment to their supposed aesthetic ideals.
Metallica, in fact, presents an extreme example. If they put out another MOP tomorrow, well, I might listen to it and even enjoy it, but I could NEVER really take them seriously again....