How we got into this mess? WinDev and DevDiv politcs.
After the Longhorn debacle, its technologies landed on DevDiv, like WCF and WPF.
Sinofsky and friends never were that keen in having .NET coming into their turf, it is no surprise that Hilo sample for Windows 7, then praises COM and C++ for Windows applications[0][1].
Then coming in this path, WinRT came to be, with roots as how .NET was being designed, before Microsoft decided to pivot it as another Java like technology[2].
A bunch of folks in WinDev, weren't happy with C++/CX, so they united to replace it with C++/WinRT, because extensions, when clang and GCC are full of extensions, promised to give back a C++/CX like developer experience in 2017[3], never delivered, went to have fun with Rust/WinRT.
Now C++/WinRT is in maintenance mode[4], and Rust/WinRT never took off, and is now Rust/windows-rs[5].
As paying customer, impacted by those childish attitudes, I would have had the whole team fired.
Finally, check the amount of bugs and complaints on their respective repos,
https://github.com/microsoft/microsoft-ui-xaml https://github.com/microsoft/WindowsAppSDK https://github.com/microsoft/cppwinrt/
And then compare with Project Reunion vision from 2021, and where we are three years later
https://blogs.windows.com/windowsdeveloper/2021/03/29/announ...
Mainly because along the way, as if those changes weren't enough, they also decided to reboot their initial approach with Project Reunion, WinAppSDK took another route, and here we are.
This is only a short overview of how WinRT went down since Windows 8, thus only those that never advocated for it, can honestly suggest WinUI, as they lack the background of how chaotic it all is.
[0] - https://devblogs.microsoft.com/cppblog/announcing-hilo/ [1] - https://learn.microsoft.com/en-us/previous-versions/msdn10/f... [2] - https://arstechnica.com/features/2012/10/windows-8-and-winrt... [3] - https://www.youtube.com/watch?v=7TdpWB_vRZM&t=2983s [4] - https://github.com/microsoft/cppwinrt/issues/1289#issuecomme... [5] - https://github.com/microsoft/windows-rs