Visual Studio itself is a WPF app, for what it's worth. I can't imagine Visual Studio being rewritten as a "Modern" app any time soon. So, it makes sense that MS will continue to invest in WPF.
When no dialogs are open, the overwhelming majority of the UI is WPF now though, to my knowledge. I remember running debug builds of 2010 that showed paint rectangles and there was basically nothing that wasn't WPF even in that first WPF version.