Double kernel in Windows - Why not?

As a Windows user I am, as much as everyone else, regularly annoyed with the Windows Update process. Booting the computer to look at a screen saying "Configuring Windows Updates - don't turn off your computer" is just not fun. 

So why on earth doesn't Microsoft do something about it?

Here's a thought: why not use a double kernel? You know, like double-buffering for rendering video.

The PC would have 2 copies of the OS. While the user was working on the active image the other one would be updated in the background. Then the user would be automatically switched over to the new version. The old version would be synchronised with the new one to get ready for the next update, and so on.

It's actually quite simple. 

Another way is to embed Hyper-V in the normal Windows distribution and turn every PC into a virtual cluster. This might even be simpler.

Either way, anything would beat the darn update process.