Anybody doing any non-desktop application development on Windows is shouldering the full risk of obsolescence within 2 year.
I would really, really like a cooperation between Google and Microsoft in the area of the utterly braindead 90ies API of Android development by switching to XAML + C# ... ah, a man can dream!
That's a somewhat harsh accusation, where are they lying? Their web page clearly explains the usage scenarios and who can use it for "free"  (scroll down to "Usage").
huh? They're the same thing. UWP is just a new name for the expanded WinRT (Metro) APIs.
The licensing ambiguity of the VS Express Editions that came before was a lot worse. At least us solo devs have a legitimate path to VS now.
Xamarin enables that.