The hardest part is for people who buy new hardware and are unable to get device drivers running on the older OSs. My machine was built in 2011, and while I've upgraded some components, namely video card and internal storage, the bulk of what I have can actually still be used on Win7.
However, I prefer WinX to Win7 - the backend stuff alone makes WinX more than worth it. I have all tiles turned off, using a start menu that is similar in look and function to Win7, but the enhancements made to things like Task Manager make 3rd party solutions not be a necessity any longer, just a convenience. The enhancements to other facets, like the Windows File Explorer (copying / moving files, detecting duplicates, etc.) make it a godsend over the old Win7 Explorer and it's sheer lack of usability when encountering duplicate file names, much less show extremely little information on progress bars when copying / moving.
To each his / her own. I'll take the backend enhancements over the older limited OS any day.
As for installation metrics, if you look just at June 2019, you get
Operating system market share