GUI builder for desktop applications in 90s were really useful in increasing the productivity of programmers. It is sad to see how complex it is to build the UI of a web application in comparison. And there is no definite answer on the best way to do it neither.

Of course now you can expose your app to the whole world. But instead of thinking what it means at the application level you spend lot of brain cycles just setting up the styles and uncoupling presentation and logic.