WPF was well ahead of his time, and unmatched in many ways... The principles are still the ones used today; an influenced many other GUI frameworks. And the current Windows App SDK with WinUI3 is a typical Windows App Framework, it's really good one... Exemple : the Photo app... thousands of pictures smoothly showing in the gallery... and after 15 seconds on the first "start' of the app... that's says it all...
And about WebView2, it's a new hybrid version of the usual EdgeWebView... Also, a nice innovation, Meaning: native access to the OS, the components have a shared memory, and it's veery good and fast (the orignal was already good). And moreover, after times, if you do not use an app using (minimized) it will unload most of the memory and components... Down to 20 -50Mb for New Outlook, or the widgets now very light, devhome, the store...
It's old news:
For OpenAI... Copilot? This the reason, not snubbing or.... why do you imagine a circumvoluted explanation, when there was a much simpler and more logical one? Occam's razor anyone? And there are already dozens of other apps...