> Microsoft's UI story is a non-starter until they get back to the point that a user can:
Why do you care about this stuff? I don't understand. Surely most developers can build a simple app with a few buttons easily in whichever framework they're using. This stuff doesn't really matter for I'd dare to say 90% of developers. What matters is how hard it is to build and maintain complicated stuff. And there WPF blew WinForms (and VB6) out of the water.
Not sure why you think how difficult it is to put a couple buttons on a page and make them do something would have any effect on the success of a UI framework. That's literally not even a consideration when we make decisions on what to use for a project.
If WPF ran on other platforms, we would use it for everything. We use Avalonia instead, and it's pretty great.
But there are 2 basic types of multiplatform UI frameworks - the ones that wrap native controls and look like most other apps on the platform, and the ones that do their own rendering and look the same on every platform. Avalonia is in the second group, so if the former is a hard requirement then it is not a good choice.