As someone who did a lot of desktop application development prior to the web just totally gutting native app development, this is my take:
The problem is that people want to make dynamic applications that have a rich UX and deep system integration while being highly portable.
Unfortunately, it turns out that "portable" is basically a Great Filter for applications. If you can't run it, you can't use it and the rich UX and deep system integrations don't matter.
So developers cast about looking for alternatives to Qt and GTK and friends. Flash and Java (and Silverlight....) all had browser plugins and offered vaguely convenient APIs for building applications with rich UXs. Unfortunately those plugins had inherent technical issues and died (or were killed, as it were).
So what platform remained that had super easy distribution and portability? A XML document format that supported directives for styling xml and some rudimentary scripting language that could dynamically change that xml and styling.
So that's what ended up getting built upon. And now, since abstraction can do anything, we finally have things resembling what we had 30 years ago in desktop applications but built on top of a standardized runtime with a JIT and a sandbox and a nascent assembly language. So that's finally what people use.
I really had nothing but disdain for web applications built with javascript/jquery soup for the longest time. They worked, sure, and printed money and all that, but I was bitter that such poor technology was what won, instead of some evolution of the existing desktop app paradigm.
Now with React et al it's finally getting bearable again. But I still find myself wishing I could just say forget all this web junk, I could write this as a Swing or JavaFX program in 10% of the time.
(It's just unfortunate that nobody would be able to use it because nobody downloads programs off random websites anymore except Putty and nobody has an (independently-installed) Java runtime anymore. Which brings us right back to the initial problem).
My memories of non-web toolkits are not as fond as yours.
You mention Swing, but I remember lots of my non-programmer friends dreading having to use applications made with Java, since they were considered sluggish and resource-intensive. They also had a certain look and feel to them that made them stick like a sore thumb compared to other apps, and a lot of people knew by looking when an app was made with Java.
Java was actually pretty fast even back in the early 2000s, but thanks to Swing et al (and to the JDK requirement), Java desktop apps had a reputation was much worse than Electron or JS-heavy websites have today. Especially among non-programmers.
Strangely, OTOH, Visual Basic had a terrible reputation among programmers, but most Windows users had no idea about it since it used native widgets.
Back then, looking native was the most important thing. Today it seems electron apps can get away with looking anything but native - so perhaps it’s time to resurrect some other desktop frameworks (I just recently started working with JavaFX and I really like it so far. Unfortunate that it is so niche)
I think the issue with Swing was that is was in a bit of an uncanny valley. If all controls were custom it wouldn't look strange.
Visual Basic was very... well, "basic", so it looked normal. Some tools like CCleaner and a lot of Antiviruses had fully custom looks, but didn't look out of place, because they were too different.
The problem is that people want to make dynamic applications that have a rich UX and deep system integration while being highly portable.
Unfortunately, it turns out that "portable" is basically a Great Filter for applications. If you can't run it, you can't use it and the rich UX and deep system integrations don't matter.
So developers cast about looking for alternatives to Qt and GTK and friends. Flash and Java (and Silverlight....) all had browser plugins and offered vaguely convenient APIs for building applications with rich UXs. Unfortunately those plugins had inherent technical issues and died (or were killed, as it were).
So what platform remained that had super easy distribution and portability? A XML document format that supported directives for styling xml and some rudimentary scripting language that could dynamically change that xml and styling.
So that's what ended up getting built upon. And now, since abstraction can do anything, we finally have things resembling what we had 30 years ago in desktop applications but built on top of a standardized runtime with a JIT and a sandbox and a nascent assembly language. So that's finally what people use.
I really had nothing but disdain for web applications built with javascript/jquery soup for the longest time. They worked, sure, and printed money and all that, but I was bitter that such poor technology was what won, instead of some evolution of the existing desktop app paradigm.
Now with React et al it's finally getting bearable again. But I still find myself wishing I could just say forget all this web junk, I could write this as a Swing or JavaFX program in 10% of the time.
(It's just unfortunate that nobody would be able to use it because nobody downloads programs off random websites anymore except Putty and nobody has an (independently-installed) Java runtime anymore. Which brings us right back to the initial problem).