I play games on my Mac when I can play them on my PC (travelling is one reason for this). I try buy my games DRM free on GOG, and play them either on Mac or through Steam streaming (yes you can load non steam games). My Mac game library is essentially wiped out by this.
And yes, there's this Arcade, but I have no interest in playing for something which is locked down to one platform.
If I want to play something and I already own that platform, why should I prevent myself from playing it because of its exclusivity?
Do you boycott Xbox, Playstation, Switch, DS etc. exclusives too?
What about Windows-only games that aren't on Mac or other systems? There are certainly thousands of those. Do you refuse to play those either?
I haven't evaluated the quality of available offerings yet, but they look good in the App Store previews, and I think they're all native Mac apps (not lazy ports), using Metal and everything.
Although yeah, you can't really own any of those games and will always need a subscription, and some may be removed in the future.