Yes, Mac developers tended to focus only on that platform, and a large portion of its user base was on monochrome for a long time. Therefore, you had a sizeable group of artists and devs who got developed strong techniques for monochrome art.
Comparatively, on PC I never saw CGA graphics which I didn't think were anything but compromised EGA images, which were themselves degraded from VGA images etc. Did anyone else play Prince of Persia on a CGA display?
I never had Prince of Persia, but I had 16-color Tandy graphics that wasn't EGA compatible, so if there wasn't Tandy support, I'd get CGA. Not a lot of CGA games would hook me into playing, when I had other options.
Comparatively, on PC I never saw CGA graphics which I didn't think were anything but compromised EGA images, which were themselves degraded from VGA images etc. Did anyone else play Prince of Persia on a CGA display?