I think that Linux (and to a lesser degree other free/self-installed O/S like BSD Unix, etc) has pretty much saturated the "market" for everyone who's actually willing to *think* about what O/S they are using on their computer.
The rest are people who just don't want to think about computers.
Something similar is happening with respect to the Fediverse, I think. If you don't *choose* to be here, then the social media you use will be one of the corporate platforms: Facebook, Instagram, Twitter, etc.
It's a hell of a filter, that kind of intentional choice. I think we underestimate it.