First thing first: what is a non-combat game? Sure, having a pixel gun and killing mobs is combat. But is Magic the gathering a combat game? How about chess? Football? Boxing? I would use the following definition: in a combat game you are winning or getting closer to winning by removing enemy game pieces while the opposing player attempts to remove yours. So WoW is combat game because you are removing mobs from the world who are trying to send you to the spirit healer. Heartstone is a combat game, because you are removing enemy cards while the other player tries to remove yours. Boxing is a combat game because your are attempting to knock out the opposing boxer while he wants to knock you out. On the other hand tennis and football are not combat games, despite being fiercely competitive.
There are few non-combat video games: racing simulators, economy simulators, minecraft (zombies are combat, but they are a flavor). Subnautica (there are hostile mobs, but they are so weak that you can ignore them). Detective story games.
Can these games be turned into productive MMOs (even using the term loosely, including games like League of Legends and PUBG where you play together and against a large group of players)? Hard to say and I haven’t seen big successes on this field. While FPS-es often has massive multiplayer (matchmaker, lots of players, living scene), I don’t know about such in car racing simulators, mostly because you are racing against the clock and not the other players.
It is possible to make a huge economy simulator game where players compete for profit without ability to actively hurt each other (combat), but unaware of its existence besides as a niche side game inside EVE Online. So no great revelation in this post, but I recommend the idea of non-combat MMOs to linger in the back of our minds.
PS: probable last thought: “we have the lowbie cornered and outnumbered”:
I just “love” the random matchmaker. I mean I like to carry, but this is ridiculous: