Can't be too mad about it though, it was free back then too.
Tack on having to pay Apple to play in their shitty ecosystem and it makes complete sense.
Wine/proton as a gaming ABI/runtime is perfectly fine, Microsoft used to do a lot to maintain backcompat and that spirit has clearly distilled into proton: it even runs games Windows is unable to (most recent example of mine is Black and White).
If I were making games I wouldn't support it either. Apple does just about everything to not support backwards compat.