People in this thread are looking at this like a "top-down" case of "when is Microsoft going to hand down the magical UI solution to everyone" when in reality, Microsoft is in the same boat as all of us which is that there is no clear direction to the future of non-web UI.
That leaves the opportunity of the future to the community. And I think we want to convey the message that 1. We have web UI options, so don't reinvent that wheel. 2. Windows is not web, so give us a UI that is desktop-centric. And in that vein, people use desktop for complex tasks, so don't try to force Windows into colorful Duplo-sized buttons and style (don't make Windows web: i'm looking at you WinUI, Xamarin,etc; all more recent Microsoft offerings ditch the complexity and move toward web design). We demand feature rich, deep, complex systems.
WPF is the most advanced UI designer ever created. WPF was made open-source (mostly) and then mothballed. It's way too complex to build from source and they are accepting nearly zero PRs from non-Microsoft sources. Maybe the move to send WPF management to the India team was a possible way to increase activity around WPF (since its repo has been drydocked and managed by like 3 people for years).
Avalonia is nice, but not nearly as capable.
I would love a potential future to be Microsoft dusting off WPF and getting serious about open-source. Fix some infrastructural problems like building from source that allow developers to begin exploring how to rebuild the rendering engine, preferably using something GPU-driven like OpenGL. There is a lot of excitement in the realm of using game engines to render UI, it would be great to have some team members be architects to design the retained-mode side of the UI interfacing with team members that are immediate mode designers, think OpenGL, Vulkan, etc. Having looked through the WPF source code, this is pretty much how it was, the WPF logic interfacing with Windows draw calls. It's just outdated.
WPF isn't fully open source, which is a huge problem. A lot of the low level graphics calls are still calling to non-open-source Windows libraries, so it's really opaque how to modularize the rendering calls. Microsoft needs to spend a year devoting a team to internally forking Win32 and then building interfaces for every WPF call into non-open-source rendering code. Then the community can actually fork some alternatives using modern graphics renderers.
I don't think we will ever see this though. Microsoft, despite languishing as a market-mover, has too much temerity to give the community this kind of control over it's core. They want WPF as an "outdated" technology to be reliant on Win32, instead of wanting it to be replaced with something more modern. They will happily keep releasing incomplete and remedial UI frameworks built atop antiquated DirectX forever.