I watched build a little bit but never got an impression that Microsoft was ever pushing metro as a ui standard for desktop apps. It was always menat to be for tablet and other mobile apps. If you don't see anybody starting a metro looking desktop app its because it's not suppsosed to be.
The biggest problem I have with Metro is Microsoft doesn't seem to know how it scales up. When asked how you'd make applications like Office, PhotoShop or even the file explorer their response is "use the old Windows 7 interface with a ribbon". Meaning the only answer they seem to have is to force the user to work with two different usability paradigms indefinitely.
So Metro is more of a Widget platform than it is an Application platform.
That said I'm not sure it matters. I'm part of the .NET community in the 2nd largest city in the US and I literally don't know a single person who has started a new desktop app in the last year (or who plans to start one ever again). Meaning Metro's inefficiencies are probably moot.