No, the majority of computers (and servers) are in regular non tech businesses and they overwhelmingly run windows. It's as much a momentum and lock in issue as it is a skills shortage issue.
There's probably one computer at most per employee, but each employee already has a non Windows cell phone. Most servers run Linux. Then there's Linux in a bunch of small devices as well. Windows is a small part of that pie and only getting smaller.
It sure is convenient. You get a user friendly GUI. But the stability, the resource intensity and the spyware. It's really a retarded decision to build your servers on Windows Server.
It's really common. The IT people know how to use Windows, and they need Active Directory to manage their Windows devices, so they just use Windows Server.