Machinima is made by people.

Cutscenes are made by people.

This is a list of every human who worked on Final Fantasy X.

You're extrapolating "400 people worked on this thing in 2000" to "no one will work on anything in 2030" based squarely on your naiive and uninformed conception of the process of creating filmed entertainment. Here, let's play a game: This is the list of people who worked on Snow White in 1937. And this is the list of people who worked on Frozen II in 2019. I think if you compare those three lists in chronological order, you will find that modern animation takes more people, not less, and that the trend is such that all of Los Angeles will be working on Frozen 5 by 2063.

SAG killed AI because the AMPTP wanted the right to scan an actor once and use them as a digital extra forever without paying dues, wages or royalties (just as an aside - "extra" is an uncredited role, so if Frozen 5 has extras, they'll have to come from San Diego). SAG fought this because every star you've ever seen in the theater played an extra for ramen money at some point and without the ramen money there's no Hollywood. You could have Googled that - but then you might have accidentally learned something. Just like what happens if you make an AI show in France - Netflix won't carry it, Canal Plus won't carry it, nobody will carry it because they're all signatories to the same contracts.

In general? If you don't know anything about the subject, and the situation doesn't make sense to you, it's a sign you need to research the subject, not that everyone who knows anything about it is an idiot. I know something about this subject. Animation I've worked on has racked up over a billion views on Youtube. And as you've likely noticed, I'll freely share well past the point anyone else cares. My one word of advice is that if I've made assertions, it's likely because I'm confident in my knowledge of the subject, and that confidence is generally well-earned.