This isn't entirely true for most games, clients run world simulation for prediction and sometimes can make authoritative changes. Almost no multiplayer games a

This isn't entirely true for most games, clients run world simulation for prediction and sometimes can make authoritative changes. Almost no multiplayer games are complete dumb terminals ,you'd end up with the same latency issues that Stadia has. Complex physics with high object counts can be difficult because synchronizing a lot of state is bandwidth intensive. Most games with lots of moving objects (RTS for example) use deterministic lockstep so only inputs need to be transferred, even if there is an authoritative server.