It's not impossible, it's just a question of if it's worth the effort. Factorio was kind of forced into it, because a) they built a save system before they went multiplayer, and b) it's impractical to replay a factorio save when loading a game, because it lasts a lot longer.

(note that factorio does a hybrid: multiplayer works like an RTS but starting from a save game instead of from scratch. If your PC can barely keep up with a server that you're joining, it can take a long time to actually get into the game or actually just not be possible)