So much crazy in here. Windows Desktop environment will not go away for a long time. Even Windows RT still has the desktop environment. The new Start Menu is far faster to navigate than the old one, even with a mouse. There is a shit ton of data to back it up.
DADES loves to spread the FUD. You can run the same exact certification tests before you submit the app so you aren't wasting time waiting for feedback. http://msdn.microsoft.com/en-us/library/windows/apps/hh694081.aspx
The price for an individual to publish apps to the store (which you do not need to install your own apps) is $50 a year. Big fucking deal. If can't swing the $50 then make it a desktop app and get a real fucking job that gives lets you earn more than $50 a year. Apple is $100 year. Microsoft's 30% cut goes down to 20% once your app hits 25k of revenue, unlike Google or Apple where its 30% indefinitely.