* Linux is the part that's being replaced, with the Windows NT kernel and this subsystem.
* The people promoting this are not aiming it at GUI programs. (https://news.ycombinator.com/item?id=11391961)
* The desktop seen on the screen will still be Windows Explorer.
So it's "Linux on the desktop", except in every particular. (-:
I am not particularly a Windows fan either and have been using Linux since the early 90s - the Linux desktop has always been quite adequate for my needs so it is personally hard for me to see why it is difficult for people to adopt Linux on the desktop. The only reasons I can see are sub-optimal driver support, some Windows application that keeps them locked (for me it is OneNote and its support for handwriting), or general fear.