The Egg wrote:
A better example would be my Sandy 2500k (which was 4 years old at the time of W10 release) silently having the rug pulled out from underneath it at some undisclosed later date (during a time when W10 is still being supported), unknowingly putting me at a security risk.
Nah. Any Sandy Bridge is only 9 years old at most, not 14+, and in any case, we're currently coasting on a long run of stagnation in what CPUs are and can do that began with, roughly, Sandy Bridge. The idea that you should be able to run a nearly decade-old OS on hardware entering its second decade, with full vendor support, is a very recent conceit in the computing world.
The Egg's example is close to spot on, maybe 6 months out as Sandy Bridge was January 2011 and Windows 10 July 2015, c.f. Windows 7 was July 2009.
If you ignore the Geode NX and C3 Nehemiah as being for embedded markets, these affected CPUs were being sold through 2004 and in systems being sold off into 2005. They would have had Windows XP installed in most cases and an upgrade to more RAM and Windows 7 would not have been unreasonable.
The exact equivalent would be CPUs sold through to 2010, so first-generation Core i on socket 1156 (and mobile equivalent), which would have shipped with Windows 7 and for which an upgrade to Windows 10 would not have been unreasonable.
With Windows 10, though, Microsoft always said this was on the cards (though with weasel words) in a new conditionality for Windows 10 on the Windows Lifecycle page:
A device may not be able to receive updates if the device hardware is incompatible, lacking current drivers, or otherwise outside of the Original Equipment Manufacturer’s (“OEM”) support period.
so we knew it was coming before upgrading Windows 7 -> Windows 10.
We saw this play out last spring, when Windows 10 1703 would not install on systems with Clover Trail CPUs: Microsoft said it had arbitrarily dropped support for these systems and security updates would cease with end of 1607, the machines would be abandonware. Where this is different is that it was not said up front that Windows 7-capable hardware could be dropped before 2020.
The idea that you should be able to run a nearly decade-old OS on hardware entering its second decade, with vendor support, is not a very recent idea at all, come off it: MS-DOS 6.22 was released June 1994 and EOL'd December 2001, minimum CPU spec was the 8088 -- released in June 1979.