I also believe Microsoft is beginning a play for an iOS-style walled garden. However, and unfortunately, I also believe most people won't really notice.
And, for those who don't agree, here's the really boiled down version of why I think Alex is right: there are now two Windows APIs. Over time, as they reach a new status quo, Microsoft will notice one will is less profitable than the other. That one will be deprecated, then dropped. Anyone want to guess which (Win32 or WinRT)?