By the way I see things going, Android is a big competitor for Windows. Android started building his own "machines" and for that will continue with an evolved Android OS. Android 5.0 will come with a desktop improved version soon. Android It’s the most popular mobile operating system, and, thanks to its open source nature and the growth of smartphones and tablets, one day it might even be the most popular operating system.
Android is already a very popular OS, but it’s primarily a smartphone OS, and then a tablet one. It will take quite a leap to make it a desktop OS, as well, but I think that’s where Google is heading with Android 5.0. and that is not necessarily the Jelly Bean, just whatever they will be launching next.
My opinion, it won't be hard at all. It will not pass long until we'll see this happening.