You can add the Flight Simulator series to the list, which spawned a vast ecosystem of add-ons, both free and commercial.
I believe though, that what you actually need as a big or small company, is good game first and foremost; the engine is secondary. When the community around a game reaches a critical mass, the very small percentage of its members who have the skills to modify things becomes significant as well.
For instance, Richard Burns Rally was not intended to be modded at all, yet the fans added new cars, new tracks, online scoreboards, etc.
In the Luanti [1] community (a voxel games engine/platform, designed to be moddable nearly from the start), one begins to see something similar as well: notable games gets mods, others don't (the former default game is a particular case; it is not exactly good but go tons of mods because of its status, and games based on it benefit from that ecosystem). Yet all use the same engine (perhaps Roblox is similar in that respect, I'm not sure if they have "reified" whole games like Luanti did).
The thing is, Minecraft of 10 years ago (or more) wasn’t even really that great of a game. It wasn’t bad, I enjoyed it, but it wasn’t that great.
What it did do right was be very open-ended and be conducive to modding, both of which were amplified by multiplayer capabilities.
I would wager that most of the fun players have had in Minecraft is from experiences that were built on top of Minecraft, not from the game’s own gameplay.
It was, as far as I can tell, the first game which was infinitely procedurally generated yet changeable. Huge procedurally generated games have a long history but in e.g. Elite or Seven Cities of Gold you couldn't modify the world in any meaningful way. The closest is probably dwarf fortress, but there the modifiable world is pretty small (or was when Minecraft came out).
That made it a great game. I think it was inevitable that the first game which combined these two, infinite procedural worlds and free modifiability, would be a huge success. Worth noting also that infiniminer, despite the name, didn't have the infinite part worked out!
I'm always impressed when I check it, that flightsim.com is still running, and still has everyone's mods going right back to the 90s. Just in case anyone still wants the poor quality airport I uploaded for Flight Simulator 2000 twenty-something years ago.
Not sure if I understand exactly what you mean by reified, but Minecraft has a ton of minigames based on server-side mods which clone other popular games. Sometimes popular Minecraft minigames/mods even get implemented as standalone games.
Battle royale games were almost certainly heavily inspired by the Minecraft minigame which predates them. Factorio has the old industrialcraft mod as an acknowledged inspiration. Vintage Story is basically standalone Terrafirmacraft (and by a dev from that, as I recall).
Arent battle royale games inspired by things like The Hunger Games or Battle Royale? All the server minigames like that that I recall from back in the days were named something like Hunger Games
Yes. The Hunger Games film and book inspired by the Japanese film "Battle Royale" in turn, inspired the Minecraft minigame. But later battle royale games were inspired by the minigame, not the films directly. A shrinking world border, for instance, is pretty important to make the concept work (in a film, it doesn't actually have to work!).
Last man standing formats were perfectly possible in traditional FPS formats too, but they weren't really a thing because to actually be fun, the format needs
1. Big maps and lots of players (more than the typical FPS)
2. A "searching for loot" mechanic, where you can increase your chances of survival by looking for good items, making interesting risk/reward tradeoffs and discouraging just turtling up in the most defensible location.
3. Shrinking borders, to prevent an anticlimactic endgame of powerful players searching for hiding stragglers.
Minecraft basically had all three since 2014, and there were quite popular last man standing formats like UHC even before they had world border (and before the Hunger Games film came out).