Any attempt to create a true multi-purpose UI builder for web applications has resulted in something more complex and hard to use than the problem it was trying to solve.
Case study:
Rewind 10-15 years and Microsoft's ASP.NET WebForms was popular (subjective use of "popular", I know), and was designed to give pretty much what you are asking for. It really did work and was great in many ways.
However, it achieved this was at the cost of a _lot_ of proprietary complexity (search for "ViewState" or "ASP.NET page lifecycle"), which over time became burdensome. Then AJAX came along, and WebForms was updated to achieve this but with even more complexity (search "ASP.NET leaky abstraction").
I was using ASP.NET WebForms extensively around this time and we found ourselves increasingly "fighting" the framework, trying to bend it to suit our specific requirements (which weren't all that radical). Also, our design team started delivering their work in the form of HTML and CSS, which was a nightmare to integrated with WebForms as it dictates the exact HTML that is used at the UI control level.
Then we moved over to an MVC framework, and were enlightened...