It's far from the only game that works like that, and the fact that publishers have been able to do this for 20 years was my point.

Even peer-to-peer multiplayer was very common. That is sufficient server software was included in the game itself. No need to download or run it on a server.

Online-matchmaking becoming more and more centralized really made this starting to go away... It has both good and bad sides. One is much larger player pool and automated matchmaking. Other side is losing communities and more custom servers with custom maps...

Minecraft, Terraria, Rust, ARK, Arma, Chivalry, Valheim, Factorio, most Valve games.

Almost all multiplayer games were like that, it only changed with the coming of MMOs.