The thing the studios don't seem to appreciate about this is that once they can have an AI generate Iron Man 7, so can any other schlub; you can say you want to watch a movie where Iron Man enters a mini-golf tournament with Genghis Khan and the 1927 New York Yankees and it'll make one for you.

There are 3 possible outcomes, basically:

1. AI is never more than a curiosity as far as movie making and this whole argument was pointless;

2. AI gets good enough to replace a lot of the capital-incentive grunt work of movie making, like VFX, but not high-level creative work like writing / directing / production design, so making AAA movies gets cheaper and the big studios lose power while indie studios gain more;

3. AI gets as good at making movies as humans are, in which case we don't need studios at all.

None of these are good for them; the status quo is actually the least bad outcome. The real game, I suspect, is that they hope that they can convince writers that AI is a big enough threat to a) make concessions in other areas to stop it and b) be grateful they're still employed at all; a world where AI actually replaces creative talent on films is a world where we don't need studios at all anymore.