Artists now realize they had signed the rights to their own work over to middlemen, who use that very work to try replacing them.
When they signed these contracts, often years ago, there was no talk of "AIs" able to "generate content". That was not even on the horizon.
"We have altered the deal. Pray we don't alter it any further."
Would they have signed these contracts if that was clearly stated in the terms? Well, if the WGA strike is any indication, I'd wager a bet the answer is "no".