There are many many .NET developers out there who are capable of writing phone apps. If you can write any .NET application you can write WP apps because it's straight forward and the tooling is 1st class. It takes a lot of time and effort to write an app and get it to a point where you are able to publish it. This is true of any platform.
I wrote the most simple app I could think of and published it just so I could say I have published an app and let me tell you it took me months because even simple apps are complex when you look at the detail; and the submission process is lengthy.
So that's casual / hobby devs covered.
Now lets talk about companies that write apps for windows phone. Well the market share is not there yet for WP so I'm not surprised that the platform is not a priority.
Journalists have mortgages to pay...
Professional full time .NET developer.