Nobody would get into the Operating System business to make money I think, the going rate is $0, subsidized by something (an ad company, a hardware company, or general kindness and community spirit).
Mac OS was though. OS X 10.0/10.1 were sold for $129 as an upgrade for Mac OS 9 users. Apple continued to offer OS X as a paid software product up to 10.5 or 10.6 (though it was also bundled with new Mac purchases).
And it's still miles easier to get Android to switch default apps and also respect your choices, than to get Windows to allow you to switch default apps and then shut the fuck about their crap.
(No, at this point Android hardly counts as FOSS anymore.)