If you assume (as MS PHBs do) that the desktop is a relic and about to be phased out, to be completely replaced with smartphones, game consoles, netbooks, tablets, and network terminals - no, it isn't.
You see, what do we use a dekstop for? To play games? Consoles. To surf the net, mail, facebook? Tablets and phones. To wrok on large and annoying excel sheets on a desk? Terminals with a broadband connection to a server.
While I'm a huge desktop fanboy, both for games and for work, I can see how management would conclude that the old fashioned desktop muight be on its way to be replaced with specific machines - and if so, Microsoft is smart to try and adapt, to get the XBone and Windows Phone to work together, to be "the same" and to work properly. The backwards idiots still using a desktop...Well, they'll go away.
For "regular" office work, you don't need a desktop pc - just a (touch)screen and a keyboard, with a connection to a server. Look at Office and the like - you can't buy them anymore, just one-year licenses. You don't really need to run anything on your end anymore.
We'll see in 20 years who was right - but, though it would sadden me, I can imagine the desktop pc being a thing of the past, adn Microsoft being a big player only due to XBox, Windows Phone, Bing,... and Office, Windows and the like being forgotten.