[jayd16]

Why is that sort of game only possible with cloud rendering vs some dedicated server architecture?

I think you'd need to go much higher in terms of how many unpredictable, latency dependent objects are needed on screen before you'd start hitting issues with client side rendering.

[cuban-frisbee]

Synchronising the game state in games now is exceptionally hard even with 64 players for any sort of latency dependent game. It's a constant grievance in most gaming communities today. If you just have to point a gpu view into the world, then it just depends on how many gpu's you can attach to the server.