Try this yourselves.
Pick ANY current maker of workstation class computers. (HINT: these are computers that people do real work on, not just navel gaze FakeBook and all the rest of it.) People want what works.
NOTICE: the OS of choice overwhelmingly (if it isn't the DEFAULT choice, it's a choice one can PAY to "upgrade" the system to!!) is... drumroll...
Windows 7 x64 Pro.
This from Dell taken just now:
Notice the OS?
This from Orbital Computers-both Win10 options are NOT recommended.
Aww, and no option for the steaming pile of garbage that was Windows 8? (Though I didn't find Windows 8.1 bad at all with a few tweaks that made it basically into Windows 7).
And yes, it's a fairly similar story with whatever high end workstation makes you choose. I notice some offer Windows 10 now, but there's always the option to *heh* UPGRADE to Windows 7.
So basically, are there a lot of people out there still 'clinging' to Windows 7? You bet. As in I can still BUY any workstation with it as the DEFAULT OS. Why? IT WORKS. Consumer gimmicks aren't needed in a workstation class computer, and that's pretty much all Microsoft has added since Windows 7.