I'm sure there's a million reasons not to, but they could even just open-source Windows 10. Leave you alone with the hardware that you rightfully purchased, and let the community police the security gaps that arise. It's beyond me how planned obsolescence especially on perfectly sufficient hardware is even legal.

That’s not what open source means / how it works.

It's likely a large percentage of that code is also used in win 10 - it’s not like 11 was a complete rewrite.