IMHO, in 5 years you might think very differently. Mobile is the future, but regular desktops/laptops still have lotsa legs, especially for business and MS still utterly dominates there. By combining the desktop and mobile OS and introducing the MS Market that gives MS massive leverage into the mobile market and even more software sales. They can be patient because at the same time, 95% + of desktops/laptops will remain locked into Windows ensuring MS a steady income while their mobile sales slowly build as users upgrade to Win8 and beyond, gradually tying mobile and desktops closer and closer together.

Hard for me to see how this will completely fail. They only have to implement it properly and wait it out. MS has shown with the Xbox that if a market is important enough they're willing to lose money short term for long term goals - and can afford to.

If MS really wants to kick Apple's butt they can now buy Nokia at a much reduced price and control both hardware and software start to finish, exactly as has been so successful for Apple. No doubt they've noticed how successful the hardware side has been for Apple.