I wouldn't say the web UI got screwed. It's just that it grew out of a markup language whose main focus was adding semantics and hyperlinks to documents. Then commercial interests (among others) focused on adding more and more functionality to make them look pretty while maintaining some back portability and voila we ended up with the kludge that's todays web pages.
Same thing. Something that was meant for doing X was shoehorned to do Y, and the shoehorning has been ugly and kludgy. Let's try to throw it away and start fresh, or at least give it competition.
