Come live with me in my fairy tale world of rainbows and unicorns!
No, seriously, if the manufacturer doesn't think it's worth putting out updates for, and it has serious security problems, toss it. It isn't worth the time or effort.
And in case you meant "it isn't an option because we have to recycle computer parts," that's what I meant. 🙂
And I am a bit confused as to how running a pseudo OS (hypervisor) on broken hardware is going to be any better than running a full OS. It's still broken hardware.
Obviously you have never needed to report to a CFO as an IT guy. Their definition of 'broken' is vastly different from IT's. "no updates" has little cash value until there is a break in.