I agree. This leads to an interesting question: can the estate of a deceased person sell or license their voice rights for new future performances? I suspect the law has some catching up to do.
This is not qualitatively different from existing situations, and will be only a minor legal wrinkle. Estates have been licensing the likeness of dead people for commercial purposes for a good while, now those likenesses are simply more sophisticated.
I'll tell you what will get complicated, copyright holders complaining that their product was used as input for the training algorithm and demanding a slice of any profits because they made the famous individual more famous by casting them.
