As an indie developer I wouldn't think about things like market shares and money, but rather focus on doing something unique and innovative, because that's what only indies can do. It's the big game companies who don't have time for quality, innovation and ideas, because they need to make money for their shareholders.
I think an AAA game for Linux or NetBSD would be more unique than a game on mac, although it would run on a mac also, if it runs on those first two.