Forza Motorsport 7
The Forza franchise sets the bar for greatness in simulation racing games. Right now, Forza Horizon 4 is the only game in the series available on Game Pass. Excluding Horizon 3 makes sense in this case since the newer title is already on the service.
Forza Motorsport, on the other hand, is completely absent.
There isn’t a legitimate reason to exclude Motorsport 7 from Game Pass. The Horizon games are far and away different racing games. You’ll be hard pressed to ever find a hovercraft in the Motorsport games.
It’s also just a bizarre choice that Microsoft has made to include all Xbox-exclusive games released after the launch of Game Pass, but not everything before that point. There may be some rights issues with third-party developers somewhere along the way, but this is Microsoft dealing with themselves here.
In the end, we’ll probably just have to wait for the release of Forza Motorsport 8 to get the best racing sim on Game Pass.