The options for an average user, who does not use steam and is not in the steam hw survey, are just macOS and windows.
The options for a serious gamer who uses steam (a tiny fraction of PC users) is clearly just Windows or SteamOS at this point, or more likely Windows + a steam deck (which is half of the 2% there, SteamOS).
Or just gaming on iOS / android, like most gamers do these days. The steam hw survey isn't really representative of gamers since the vast majority of them game on consoles and phones.