After almost two decades of Win32 being the best way to write apps across the Windows platform, that has been upended in a year or so. That's a big deal. But we now have two competing stacks on the phone vs tablets/PCs which can't be a good place to be.
Disclaimer - I know no inside details of Win8 UI/development platform plans from my time at MSFT.
You're RIGHT though, it's just the examples aren't so good. In recent memory: WPF, Windows Forms, MFC, .NET Remoting, DCOM...
They actually had a session at a recent dev conference (I saw the video) where they told you all about the underwhelming list of new features coming in WPF. The main message: WPF isn't dead! But it made things pretty obvious.
The trouble with a company the size of Microsoft is that there are so many people creating so much STUFF that it's nearly impossible for them all to work together. It may be better for them, as a company, to allow their various branches to function independently while exposing an inconsistent API story to the outside world. The alternative would be to make everybody talk to everybody else, causing all work to come to a grinding halt.
If they're going for lowest common denominator apis like HTML/JS, then you get subpar LCD applications that Apple can blow away via better support in native apps and Apple OS specific APIs for Objective-C/XCode. Windows devs will then feel like they can do better than HTML/JS and move over to Objective-C/XCode and Apple.
In fact I'm strongly considering moving to the Apple camp after being a long time staunch MS supporter for my entire career.