Microsoft is slowly exiting the desktop market. They are doing this by developing an app market and moving their business apps to the cloud and pushing them hard. There is a very strong rumor that Office 2013 is the last desktop Office (Office Web Apps Server works extremely well for most use cases and is the basis fro Office 365).
They are doing fantastic in the enterprise apps market (Dynamics, Exchange, SharePoint, Lync) and Server 2012 is a stunningly good server OS with Azure being a heck of a platform, too. They don't need nor want the desktop OS market; they want the desktop APPLICATION market... it's where the money is.