Also, an obstacle that no one really talks about is DRM. Invasive and commonly used DRM programs like Denuvo are Windows exclusive, and as they’re completely opaque and proprietary, this blocks the Gaming publishers from porting the game to Mac or Linux, even if they wanted to.
Denuvo is not a problem actually. It's only a problem if you want to release a Mac port on day one with the Windows version. Otherwise by the time the Mac version is out many developers have already removed Denuvo. It was removed from Metro Exodus only a year after its release and exclusivity on Epic.This year the Mac and Linux version arrived. Borderlands 3 for Mac was released one month after the Windows port on Epic and didn't have Denuvo. Shadow of the Tomb Raider for Windows still has Denuvo but the Mac/Linux ports don't.