[Tangurena4]

> And you need a method for dealing with desync where the clients and servers don't agree on history

In MMORPGs, the desync frequently occurred from hackers. The end result was that all of the processing ended up on the server, with the client only rendering what was delivered from the server and sending movement/keystrokes to the server for processing.

> the model that has won out so far is one where the server is thick and the client just handles sending commands to mutate server state as it can

This is the natural result of having to deal with hackers and cheaters. Everybody running online games (re)discovers this.