When I think about games as rulesets, as opposed to interactive stories, I think about games that have lasted hundreds or thousands of years. Chess, Go, Mahjong, Poker. We think of video games more ephemerally than that, often, but no reason they have to be - they can last forever!
Advanced & BECMI D&D seem to be TTRPG rulesets that can last (with variations). I've mentioned that I don't think I ever need another driving game beyond Forza Horizon 5. Destiny 2 after Final Shape will be interesting. And folks have made Morrowind/Oblivion/Skyrim last.
None of this even gets into the broader "retro" game space, with folks endlessly replaying games from 40 year old consoles. Sampling the whole history of video games is a great way to think about what makes games last in memory and what makes them stay entertaining for decades.
