I work in healthcare IT. The idea of an OS being beholden to a subscription is a non-starter. Talking desktop, device, server, whatever. We value security and stability (in every way the word stability means) above all due to the extremely complex and strict rules and laws we need to abide by. I can only imagine that most governmental groups are of the same mindset.
That said, there's always Macs. The cost of training personnel isn't as high as many think (most users barely know how to operate a computer, rather they focus on the software / apps that they have to use for their jobs). A transition to Mac would mostly incur costs on the hardware, and that can be negotiated with Apple when you're talking massive volume, education, government, healthcare....
Linux on the desktop is another non starter. Too many issues with effective administration at large scale, across complex environments.
Any who, if Microsoft was crazy enough to make their desktop OS subscription based, I'd just buy a Mac and call it a day. I am fine with Macs, and for work I connect to various virtualized desktops anyway so my OS is moot.