Way to miss the point about servers
Again, the portion of the claim I was discussing was about Free Software, serious computing, and servers. The billions of IoT edge sensors and Android devices are not servers. The dominance of OSS on the Internet is freely acknowledged elsewhere, but its size relative to the whole IT estate is over-estimated. There are other non-free, proprietary OSs than Windows used in the last few decades. HP-UX, for one. There is plenty of Windows in the Cloud, even it's mostly Azure.
I haven't used Windows recently for serious computing either, but that doesn't mean folks aren't doing it. I don't claim it "must be done from proprietary", only that people can, and do. I prefer BSD, but that's just as anecdotal as your reports.