Well, i think they can pretty reasonably argue that the companies can not take their body image «for free forever» like they are trying to do, it is just stealing at that point.
If Disney wants to , say, take Harrison Ford body and make an Indiana Jones 6 with ''him'' (an animated rendering of his body), then they have to pay royalties, negotiate a contract, etc with the person, the same way any of them would do with their IPs.
In general, everybody should have their body as their own IP really, by default and retroactively. With largely the same rules as the IPs of these mergacorporations, so they enter public domain after a while too ( i really want my AI-generated Buster Keaton short films ... )
The actually analogous situation with us mortals getting replaced by AI, is if the Studios just straight up invent AI actors and actresses from the start and register them as their IP, and does not hire real life actors. So, an AI John Smith, that is just a program owned by Disney that their production uses in films (can we really call then films at this point ? for me everything will just be Animation henceforth). This is more probable in the long term, it even already exists in some subcultures, like some J-pop singers that are programs made by fans.
But would it be possible to make AI John Smith "from the start"?
Every AI John Smith characteristic would be based in a real human - unless AI John Smith is a 100% alien lifeform. That applies not only to appearance, but mannerisms, voice, accent, etc.
AI cannot create a 100% "original" human, because it will always be based on information based on real humans.
The analogy is that any text or code "created" by AI is based on learning from texts and code that were written by humans.
Unless Harisson Ford has rights on the "Indiana Jones" franchise, where would be the line for his legal claim? Could AI create a character to play his part that looked nothing like him, but still mimic the way he moved? And how close the resemblance to Harisson Ford could be? Who would judge that?
What about James Bond? So many actors have played it, and there are gestures, sentences, behaviors which are part of the character, not of the actor. How would that be dealt with?