Delphi and Visual Basic 6 were definitely not the pinnacle of UI development.
For example, all layout was pixel based. Making windows resizable required much complex ad-hoc code, and internationalization was hard as well. Very early in my career, I have spent person months clicking through every single screen in a large desktop application to find words cut off due to words having different lengths (measured in pixel) in different languages. I knew what "Ok" and "Cancel" meant in half a dozen languages. At the time, Java was really breaking ground with container based layouts in Swing. Delphi and Visual Basic caught up only in the .NET era.
For example, all layout was pixel based. Making windows resizable required much complex ad-hoc code, and internationalization was hard as well. Very early in my career, I have spent person months clicking through every single screen in a large desktop application to find words cut off due to words having different lengths (measured in pixel) in different languages. I knew what "Ok" and "Cancel" meant in half a dozen languages. At the time, Java was really breaking ground with container based layouts in Swing. Delphi and Visual Basic caught up only in the .NET era.