Yes, but those developing for Apple OSes would have adopted whatever OS Apple used.
The developer who pick it because it is a Unix are people who developer for Unix like OSes, mostly for servers, so they mostly do not produce software that drives adoption by people who are not developers.
The developer who pick it because it is a Unix are people who developer for Unix like OSes, mostly for servers, so they mostly do not produce software that drives adoption by people who are not developers.