Windows needs to be two versions.
Business/Enterprise/Legacy (LTSC) and Consumer/Creative/Gamer (think macOS).
It doesn’t need to be harder than that.
Then Microsoft could start to move the Consumer version forward just like Apple has done with macOS the past decade. I mean tightening up security by removing legacy components, removing Control Panel, getting common software into the Store (like Chrome) etc. Consult with Craig Federighi to get a good balance between features and security.
It isn’t rocket science. Apple has done it. They even found time to develop a decent SoC…
It isn’t about developer buy-in (although, that is good to have). Apple provided a viable path forward for macOS application devs, not a crazy UWP rewrite proposal.
You may call macOS legacy. Would you call it insecure? After all, that’s the real question.