How are they "dead"? What are users going to do if MS makes Steam completely inoperable on Windows? Whine and complain? Users have already proven they're completely unwilling to leave the Windows platform, so MS has every incentive to screw them over as much as they want.
They're not going to be able to get users excited about their products like with Apple, but they have a huge userbase that just isn't going anywhere, ever, so they might as well come up with any method they can of milking these people for money: advertising baked into the OS, the Windows app store, spyware and selling info to marketers, etc. Why shouldn't they? And exactly what incentive do they have to not be as overt about their customer-screwing as they want?