We've forgotten how to do it - the idea of dragging a button offends our modern sensibilities. You can't just drag a button, what about the layout?! What about responsive design, how will it look on a 300x200 screen and a 8k one? What about scaling? Reactivity?
Yes, and most of these problems can be very well mitigated by just implementing some sort of a layout constraint system. Xcode does it (AutoLayout), however, it's not nearly as pleasant and straightforward to use as the old VB form designer.
Visual Studio's form editor had decent solutions for that. And most application developers don't care about tiny or huge screens anyway, applications will just be broken if you resize them too much. The software stack they're using should allow them to make the design work on any form factor and resolution, but most of the time nobody cares about those edge cases.
And even then, UI designers worked on abstract units and changing screen density changed the size of the elements (if you used bitmaps you would suffer, but that would be on you). VB6 paid for my first apartment in Brazil.
