These steps are necessary stepping stones in getting the thing good, the question is, given Microsoft's tendency to abandon UI frameworks halfway, apart from the classical ones listed above, is if they will keep it focused until its gets as mature as those.

As long as it only applies to Microsoft employees, maybe the pain using C++/WinRT will finally improve the Visual Studio tooling for the rest of us, but I doubt it.

Thus better leave WinUI to the Windows team.

The only good thing to say about that is it removes the stupidity of using Electron (or the Microsoft Edge equivalent) for built-in Windows apps and the Start Menu. SMH.