Mac computers are more capable than they have been for a long time, if ever. All it takes is for a developer to have the will to make it work on Mac.

Recent game releases for Mac include: - Lies of P - Baldurs Gate 3

Soon - Resident Evil 4

Slightly older release - Resident Evil Village

Maybe Valve just can't hack it? They also flamed out on their VR support a few years back, only releasing a few betas before they gave up and cancelled the whole thing.