"Windows Metro" as a separate OS

Hello!

I was just pondering some next steps that Microsoft could take for the next release of Windows 8/9. I came up with this simple design from Windows 8.1 currently.

What if they separated the Windows Desktop from Metro completely making them independent of each other. If you buy a computer with Metro installed, you can then buy the Desktop separately and install it. The desktop would appear as a tile on your start screen. Moreover, you could install several different OSes if you would like.

This would solve the problem of having a desktop on the Surface RT and Surface 2 (although I have to admit that it is helpful to have it). Also, it would help solve the problem if Google becomes more popular with OEMs: Microsoft could make the Metro interface installable on Chrome devices.

Ultimately, I think that Windows Metro should be free for OEMs to install on their devices, while they can still charge OEMs for the desktop interface.

I have a picture that I made, but I cannot figure how to get it on (is there a way to post pictures directly from your computer?? Sorry, I'm new to posting here.)

Here's the picture on SkyDrive.

Let me know what you think about this. This was an idea after I read this earlier.