You'll also find that the malware protection suppliers tend to drop support for obsolete OS versions eventually. Maybe not immediately after support ends, but I know that at least one AV vendor dropped support for W2K3 some time ago and that's only been obsolete for 18 months.
Checking today I was surprised to see that ESET is still providing new versions for W2K onwards.
Yes...I'm paranoid about cyber-security because it's a large part of my job...but if you'd seen/heard half of what I've seen/heard you'd be paranoid about it too!
I understand that you have whole different concerns from the owner of a wx server that's double NAT'd and never used to surf, but can I ask if you are not at all concerned about Win 10's
telemetry and propensity for considering your PC to be an extension of Microsoft's network/cloud? Or maybe they give you corporate types more control than us regular folks?