Why Stronghold crusader HD (GOG.com) have version on mac, but steam version have not?

[Dlav]

https://www.gog.com/game/stronghold_crusader


GAME DETAILS
Works on: Windows (XP, Vista, 7, 8, 10) and Mac OS X (10.6.8)



Steam version work on Windows platform only.

[Péťa]

I am also curious.

[Jackee4]

curiosity