While we pull for Microsoft to make a comeback in the mobile market, Windows Phone 7 has been on the market for nearly a year. Granted, WP7 was a bit rushed, the Microsoft brand was able to do more for its mobile effort. It really does speak to the direction that its competitors like Android and the iPhone has taken.
Mango, the next major Windows Phone update, is due to come to the market in a couple of months. Perhaps, this is just what Microsoft fans are looking for and might be enough to draw away some defectors from other platforms.
Furthermore, Mango's push will be aided by Nokia's global muscle. One of the things about Microsoft is that its first attempt rarely succeeds but it learns and adapts quickly.
One other note I like to mention is whether all of the mobile revenue comes from Windows Phone licensing and related activities or does some part of it have something to do with patent royalties Microsoft receives from HTC.