Re: Stop me if this sounds familiar...
"MS has a history of "supporting" non-x86 CPUs then burning its customers (Alpha, MIPS, PowerPC, Itanium, ARM) so I would be suspicious."
MS cut the support early for the first three as they probably didn't get too much interest for those ports. I sure as hell wouldn't have bought a rather expensive MIPS/PPC/Alpha system to run NT back then (20+ years ago), when the commodity (and cheap) 486s and Pentiums did the job well enough.
MS dropped Windows RT because of poor sales. They burned almost a $900M on the debacle, and since there were very few customers for it why would they burn untold man-hours to port Windows 10? Windows RT still gets security updates for years to come, AFAIK.
Itanium support lasted until 2008 R2 Server, RHEL dropped support around same time.
I'm sure there are a lot better examples of abysmal MS support than the NT era systems or Windows on Itanium/ARM. I'd start with the different Windows Phone versions.