When I first looked at WinRT app development I thought "how are they going to sell it with these limitations and incompatibilities?" and they did not. UWP was a slightly improved version on WinRT, but it still had some of the same core issues. Luckily, Microsoft has some kind of exit strategy already - I just wonder where that leads.

That all being said: Microsoft should still invest in their desktop stack (especially WPF / .NET for desktop applications in general). Bringing the positive parts from UWP to the established frameworks would be a big win for everyone.