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.
