My thoughts are that they didn't come out against their label because they already have legally binding contracts (probably signed a long time ago) which don't give them a legal leg to stand on (they signed the contract, so it's a little too late to complain about not getting enough of a cut.)
Well, I'd argue that it might be possible for artists to bring a collusion case against record labels charging that they conspired to pay artists very little for their music and not giving them any other feasible outlet. But I get your point nonetheless.
I guess they figured it'd be easier to go after (in their mind) the second-biggest factor that was cutting into their bottom line, which was file sharing.
When, in reality, it's bound to be unlicensed mass-produced CDs from China, etc.
Obviously they neglected the impact of public opinion. Of course, if they were smart, they'd realize that they could also help their bottom line by putting out better music...
I think that the majority of the public and, in particular, Billboard disagree.
_________________________
Bitt Faulk