alt Hacker NewsThis is kind of a shallow assessment of "slowness". Slowness is a feeling, not a fact. Network is slow as a rule relative to other parts of the stack, but it is not usually what contributes to the feeling that your software is slow. It takes a good amount of incompetence and arrogance to cultivate that particular experience.
Fair, it's shallow because I was succinct however, I do understand the problem space more in depth than this.
But if I were to pick one single thing that would speed up the most UIs across the board, it would be poor handling of the UI in networked systems. As you noted, that doesn't mean eliminating them, it means handling the inevitable in a way that doesn't tank the UI feel.