Also, in games, most "messages" are a few bytes, and you pack dozens or hundreds into a single UDP packet. Each of the messages will have application specific o

Also, in games, most "messages" are a few bytes, and you pack dozens or hundreds into a single UDP packet. Each of the messages will have application specific ordering/reliability/latency trade offs. No existing IETF or ITU or other protocol comes close to the efficiency gotten by designing the stack correctly for the application. But, why would games go through the trouble to do an RFC? It's not like you're going to have DOOM talk to Overwatch. And, while the router will see those two games as the same, the internals of the packets reflect the internals of each game. Hence, similarity ends approximately at the UDP level -- which is what the internet cares about, anyway! (In fact, I even tried to get a standard for the most basic cross have entity transfer 10 years ago, with zero uptake.)