You do not buy a perpetual support license with those OSes.
The cost of those operating systems was for a given list of compatible hardware. Windows 7 support ended, Windows 8 support ended, and Windows 8.1 is no longer sold, but still supported (so security patches still arrive).
Like it or not, I understand MS, as backporting and re-valdating anything is a huge cost. Been there, done that, although for embedded systems.
1) this is almost certainly a partially arbitrary limitation, since Kaby Lake is architecturally identical to Skylake, yet one is supposedly supported and the other not, and
2) AMD Ryzen hardware has already been sold with the explicit promise by the vendor that it will have Windows 7 support; Microsoft is now breaking that promise.
Also, you may be misinformed regarding how Microsoft's support lifecycles work. MAINSTREAM support has ended for Windows 7 -- which means no new features -- but it still receives security patches until 2020. So does Windows 8 and 8.1. In fact, even Windows Vista still receives security patches until April 11th.
It seems like what's happening here is that they pushed out a patch that maliciously UN-supports certain hardware. I was running Windows 7 on Kaby Lake fine yesterday and receiving security updates, and now they're telling me I can't. Why? All the chipset drivers are third party and have nothing to do with Windows Update.
> You do not buy a perpetual support license with those OSes.
Well, when it come to Windows 10, I would say that yes, we are effectively paying for a perpetual support license. If Microsoft is comfortable throwing ads at me as a part of normal OS operation (and they are, and keep putting them in new locations I have to disable individually), I'm comfortable saying that I'm paying them perpetually.
Most people are paying them money for a version of windows that works with the hardware they are buying. You won't be able to find an OEM selling win 7 on a ryzen box, for example.
If you buy a separate license, you should be aware of compatibility as well.
Isn't that what we pay them not insignificant amounts of money for?