https://cloud.google.com/compute/docs/accelerator-optimized-...

A system with, say, 8 large GPUs could easily generate graphics for 24 or more players and support a complex world as in: something like

https://en.wikipedia.org/wiki/Kowloon_Walled_City

where you can walk through all the doors. A single SMP computer (kinda like couch multiplayer but with multiple screens attached) would run the whole thing which would put a limit on the player count, I can't see it exceeding 100 but the selling point would be the complexity of the world. If anybody could build a gaming cluster that could scale up to more players it would be Google.