But that is going to soon change as MS is working with Intel to launch Intel powered phones (x86). [1]
Regardless of whether Windows phone succeeds or not, I believe the path they are taking will eventually be where all the OSes will end up. The saying "The best camera is the one that is with you" may hold true for computers in the future.
Imagine hotels & coffee shops offering a dock for rooms/tables and the only thing you need is your phone. Plug it in and voila!, your personalized desktop with all its settings and data. This might even be secure, cost effective and more efficient method for portable desktop.
[1] http://news.softpedia.com/news/microsoft-launching-intel-pow...
Plus people keep forgetting that there aren't any open options for the radio OS.
Of course, there's relatively little that truly takes advantage of that set up, and making the user experience more pleasant would make a huge difference, but android understands mouse and keyboard input just fine. Microsoft may be somewhat further along on this front, but I don't think it's as much as you think - the apps that can run in this way are not full windows applications, and there are relatively few of them at present.