Why? You may end up with something that doesn't get much attention anymore, but none of the official gui approaches have ever been removed as far as I know. Win32, MFC, winforms, wpf, winui, maui are all still available and apps using them are functional. Even winjs still works apparently, even if it was handed over.

I wouldn't start an app in most of them today, but I wouldn't rewrite one either without a good reason.

Well a number of them have horrific bugs in them which have zero attention. At least win32 has an abstraction level which allows you to work around them.

There’s a fun bug on WPF and form backgrounds for example which means on fractional DPI screens the background is tiled unpredictably. Had to patch that one up rather quickly one day and it was a mess due to how damn complicated WPF is.