In the long term, AI is going to be such a massive force multiplier that you'll be able to get away with non union writers and actors.
If all goes well you will be able to produce a film in your basement and have it rival the quantity of the current big boys. That will be a long while, but in the meantime any industry that loses a 2x productivity boost will die to its competition.
Especially in the modern world. Centralized stars and production is crazy in a world where you can pull out a camera and buy a rendering supercomputer for a few thousand dollars.