Some people (I suspect a lot of young and motivated developers) think that UI development should be easy and elegant.

But consider that a UI is 100% state management and side effects (so fundamentally imperative and asynchronous). On top of that it takes about three revisions for any tool to require bespoke display of something (everybody has an opinion). They also bring a layout engine which is best expressed in constraints.

And somehow we are trying to shoehorn all this into a functional paradigm.

Mostly is, with native toolkits, Web should have stayed for hypermedia documents, but here we are.

I have used and programmed enough kinds of UIs, since I got coding into that Timex 2068 in 1986.