In the real world of Business and Enterprise, where Microsoft(still) holds sway, Bosses expect fast( Matter of days/weeks for banks), robust software development and deployment to remain competitive.
UWP (C#/XAML) has failed in this arena. Compared to 15 year old Windows Forms, UWP is not the right, or effective, tool for this arena. (This arena is NOT interested in mobile/ scaled Apps, it just wants business software deployed to its desktops)
Some Developer perspectives on why UWP [C#/XAML based] Failed:
a) The UWP Platform is narrow, does not offer the deep API to exploit the Windows client side platform
b) UWP is feature incomplete, and relies upon Third party to develop basic Business capability (Aka No basic Charts available in the core ToolBox) its a NuGet Hell to recover base capability with all the associated Third Party Support and Reliability Risks
c) The XAML developer experience is still a bag of pooh, with Visual Studio XAML designer banging out on obscure poorly defined errors, and over complex styling code (There is a good reason why CSS is separate to HTML)
When LOB Business developers can be more than twice as productive/effective coding in Windows Forms than UWP, then business will never take up UWP seriously.
Basically Microsoft has let the Line of Business community down, in depreciating classic .NET for the inferior UWP technology. Of course for mobile and commercial Apps UWP makes sense.