>I already have basically every other sim, purchased on Steam and installed.

You do not have the "sims" I was talking about, which are the ones used in automotive industries and who are using tire models which are certainly more advanced than what is found in any game.

>I can just jump into them, and for example enjoy AMS2, or LMU, or iRacing tire models instantly.

Which is the difference between a game and engineering software. In a game the tire physics should be fun, in engineering Software they should be accurate.