There's always The Ur-Quan masters: https://sc2.sourceforge.net/

Traditional games cannot iterate because they exist as an agreement by the players, they don't have anybody who "owns" the game to improve it. Notice that in tabletop and modern boardgaming, where they do have a coherent owner, we do see revisions and iterations. If I play Dungeons and Dragons today, or Cosmic Encounter, or Magic the Gathering, it's not the same game as 25 years ago. Not as radically as video games have changed, but still they have evolved because the owners of those games have iterated on them.

To my mind, the non-transient part is that these old games have clear successors that hew very close to their original form that still draw new players. If you want to play Quake, you will find a massive number of games that play very very close to Quake and have active playerbases.

Really? This might be true for multiplayer games (though people still play Counter Strike 1.6 I guess) to some extend but for single player games I don't see how they are transient.

Most of the games I play are ten years or older. Admittedly lots of games that I never got around playing as a child. Also, retro gaming is huge.

With gog.com it is pretty easy to play old game⌊. Though many more modern games might get lost forever because they require access to certain servers. We need legislation that forces publishers to open source games including the server-side code once they stop supporting them.

Well some games are eposidic. I play a little fortnite, and the island keeps changing, significant things come and go (some weapons, map locations, bosses, ufos, boats). Its keeps it from getting stale, but you can never go back to the way things were..