Desktop platforms in general are in massive disrepair on all platforms. As Walter points out, if your app is a typical enterprise application and would work well as a Web application and doesn't have specific requirements that require use of a local machine, building a Web application is usually the best route to take. For most business applications this is the way to go.
For Windows desktop apps hard choices have to be made.
I have several WinForms apps I sell and one popular WPF application. The WinForms apps are easier to build and more similar to FoxPro UI applications, the WPF application looks much nicer and has more flexibility in the UI. As the WPF app (Markdown Monster) is a general purpose editor app the latter was actually a fairly important factor and WPF fits that well.
To make things even more complicated Electron (Chrome and Node based local Web application) lets you build HTML based applications that can access client side resources. Electron is a decent choice if you're familiar with Web technology, but you basically are responsible for the entirety of your UI and framework. There's no real UI framework and you have to fall back to using something like Bootstrap or Material design etc. for providing you the base UI features which tend to be un-desktop like. I've started Electron projects on a few occasions and abandoned them because it was just too much work to deal with the UI. On the upside Electron apps can be cross-platform although to do that right and deal with OS specific features can be a huge time sink as well.
Microsoft is pushing hard for Universal Windows apps, but frankly if you build one of those you might as well build a Web app, because these applications have many limitations that disallow them from doing things that you might need from a desktop applicatino in the first place (although Printing is one thing that you can do from it). UWP is like a hobbled WPF unfortunately and because of that uptake has been very lack luster.
At Build this month Microsoft revealed plans that they are planning on moving WinForms and WPF to .NET Core which seems to point at the demand for these technologies is there and Microsoft is not walking away from them. There have been improvements in both platforms with each .NET release, but they are mostly small system level/UI level changes that improve performnce and compatibility. A while back MS shared numbers of what MS desktop technology is most prominent and WinForms topped the list followed by WPF and UWP a distant third. I think Microsoft is coming around to see to keeping these older technologies alive and making them work better (like High Definition support for WinForms) is worth the minimal effort required. These tools are also quite mature. WPF has lots of online content and support controls so the fact that there's been little new stuff is really not a detriment.
In the end I think the questions you really need to ask is:
* Can I build my app as a Web App to get done what it needs to get done
* If not what desktop platform works best for my needs
+++ Rick ---
>... or is it the development of "fat windows" clients that are dying out, even for line of business projects?
>
>I'm asking because most of the articles and add-ins are more than 5 years old.
>
>But then, what exactly (ok roughly) are the options?
