I think the problem with MS is there's very little exclusive MS content now. Halo has gotten long in the tooth. Bioware has gone multi-platform. Viva Pineta seems dead. They closed studios, released Bungie.
What's left? Fable, and Rare and Forza. Hardly compelling reason to remain exclusively loyal. At least not when compared to Sony and Nintendo's extensive 1st party offerings.
Edit: Put GT meant Forza. And there's Gears but that's going to start to get stale as well.
MS needs some exciting new IPs if it's going to win over people next gen. Or at least more of them. We haven't even seen all of Nintendo's or Sony's come into play yet this gen.







