Mac used to be the same story, but now I would bet that at least 10% of indie game sales are on Mac.
If you're using tools like Unity, then shipping to Linux is not nearly the headache it used to be.
I play a lot of games, but thanks to this shift I no longer have to run Windows (can't play overwatch but I can live without it for now). I, for one, am glad I don't have to double my purchases.