You're right, it is. I did a lot of C#/WinForms development back in the day. I never liked it but I liked the people I worked with and the company I worked for so I tolerated it.

Reasons? OK, this is going back about 20 years but, and without going on a massive ranty screed [EDIT: oops, failed], compare something like Swing's JTable to WinForms' DataGrid. One is a really nicely designed and abstracted component with a fully pluggable architecture and an out of the box capability to deal with an arbitrarily large data model (perhaps within the limits of 32-bit integers) and the other... isn't. I tried with DataGrid, I really did. I thought other developers at my employer were "doing it wrong" by reaching for third party controls from the likes of DevExpress and Actipro but... they weren't: I was wrong. If you wanted a proper table/grid control that was easy to customise and extend and wouldn't chunder on millions and millions of rows of data you forked over the money to DevExpress for their control and then you got on with your day solving your real problems that you could charge customers actual money for.

We leaned hard on third party control libraries from DevExpress (particularly grid and tree), Actipro (wizard), and Syncfusion (again, grid). To me, with WinForms, and bearing in mind I'd come from Java Swing (which is by no means perfect) it was really weird working with a UI toolkit where what came in the box wasn't sufficient to build any arbitrarily complex UI I might desire. Weird. And frustrating. Same for the lack of abstraction/separation of concerns. In my Java days, when I wanted a wizard I ripped the one out of NetBeans: I did that in at least two prior jobs using it as the basis for multiple wizards across the relevant applications.

And WPF... although architecturally a lot better, IIRC it didn't even have a proper table/grid control: you had to build your own, and when you start thinking about how rich a proper table/grid is, taking into account accessibility, keyboard shortcuts, picking up OS level settings (palette, scaling, etc.), making it behave like a table in any other application on Windows, I just couldn't be bothered building all that... so then it's back to third parties again.

I don't know what third party support for these frameworks is like nowadays but, fundamentally, for the sort of independent experiments I'm working on I don't want to either (i) fork over hundreds or thousands of dollars to third parties for (I think) basic functionality that (I think) should be available as part of the framework and should have been there since day one, or (ii) spend time wrangling the framework to implement this basic functionality because it isn't a core part of the problem I'm trying to solve or the value I'm trying to deliver.

I'd rather just use Qt or something, which at least has what I need.