The core technology at the heart of both VB6 and Delphi were the Win32 Common Controls, a set of native code GUI elements that are still present in windows. They offered a consistent toolkit across all windows versions. At the time, this was most GUIs.

It is unlikely that any one set of native GUI elements and library calls will ever be applied across all GUIs ever again. The constant churn of languages, the web stack, the vast size range of displays all combine to a situation where GUI application development receded from a high water mark, and it's all downhill from here.

The tools are worse than they were, and are unlikely to recover.

What you can show/build with HTML/CSS/JS hasn't really changed that hugely in the last few years. There are RAD tools for React apparently (retool?) and I don't doubt they wouldn't be appropriate for all uses, but there's plenty of cases where you just need to throw together something quickly where being able to "build" the page layout visually would be extremely helpful. I sometimes get the impression many React-based sites you just get whatever layout happens to be the default (based on HTML5/CSS specs, and whatever libraries/out-of-the-box stylesheets you might use), even if the exact outcome doesn't really match what's been asked for by the UI/UX designer (who almost certainly did use a WYSIWYG tool to come up with the wireframes/static mocks etc).