I share/understand your cynicism, but am hopeful that Microsoft is really turning a corner with the latest management change. The messaging has certainly been a lot more cross platform. And something like WinJS you don't do in a day or a week, I could easily believe that throughout its life it was a 'windows only' thing until the strategy changed and now its a cross product thing but carrying a lot of technical debt from that previous positioning.

Lucky for both of us there is a built in barometer for seeing how committed Microsoft is, in the form of the Github issues list.