Why would Apple ever invite Valve to potentially do the same to them?
When Cyberpunk, AC, and a couple other AAA titles came to macOS, Apple made a big deal of them being in the mac app store, specifically. They didn't go out of their way to call out that they run on mac, you can get them from Steam, etc. The big deal was they are in the app store.
That's where Apple wants mac gaming to happen so they can get their 30% cut.
I wish that weren't the case, but Apple's gonna Apple.
It does suck if you just want to play games on hardware you own that can handle said games.