[eru]

About the first one:

Even going about this very naively, you could at least use it to train a model against a supercomputer running the game, and then run the inference on much more modest end-user machines.

But you can be much more ambitious: have you seen eg style transfer? So you could probably do a bit of ML black magic to train your model on GTA, and then point it at the Google Earth data to get a GTA-like set in real-life London.

Or you could use something like style transfer to go for a cartoony look, or add ray-tracing like effects, even if you didn't have these effects in your original engine.

Or you can use a pre-trained model (eg on GTA), and then spend a relatively modest amount of extra training to get a different kind of game, eg one that has magic or so.

About the latter part: I do think their model is already running with some state. But even if it ain't, that's a relatively small thing to add with already known standard techniques (or you can come up with new techniques.)