I do not understand the facination of Ribbon and WPF. .Net 3.0 does not even have Ribbon at all. So, why are we talking about Ribbon which is unrelated to WPF?
Anyway, VS WPF >>> all older VS because older VS are so messed up when using high DPI setting.
And the reason why MS doesn't have many WPF apps? MS is not Google who likes to screw up existing formats, in this case, MS didn't want to screw XP users who doesn't know how to install optional Windows Updates. Just like many MS sites still using Flash instead of Silverlight, like I said, MS value users more than their technologies.
Expression Blend is using WPF. Go try it.
As someone's examples are all native app based. The moral of story, some devs like to make crappy eye candy on native apps. And if they can use WPF, it is just easier to make crappy eye candy. WPF is a tool, not a design guideline. Surely it is slower. I haven't managed to add 40 thousand images as effeciently as WL Photo Gallery.