As has the rest of the world, and we will just put it on the list of UI frameworks Microsoft did not completly implement, fully support or considering "the default".
So we stay stuck with the status quo: There's no official UI for Windows, still.
There is Win32, that has made us company for several decades, is kind of ok, definitely much better than Motif, the official UI for much UNIXes, before Linux took over.
As has the rest of the world, and we will just put it on the list of UI frameworks Microsoft did not completly implement, fully support or considering "the default".
So we stay stuck with the status quo: There's no official UI for Windows, still.