The Soloist
Hero
Interesting metric. 10 years is a long time in the business world. Savage Worlds would qualify. Shadow of the Demonlord (2015) still gets adventures regularly.It's still relevant 10 years after launch. The company that published it provides steady employment for its employees (even if just a one man publishing house) producing content for it without big boom and bust swings.
In other words, it is to paper what Stardew Valley or Skyrim is to video games.
There is a short list that meet that criteria. CoC and D&D are certainly on it. Traveller might make the cut. Warhammer Fantasy Roleplay, maybe? Castles & Crusades is starting to get to that point.