Evolution of a UI isn't as important as evolution of the features the UI exposes. As for whether it feels any faster, depends on what you're doing. To give an example, Excel functions can be calculated using multiple CPU cores, which AFAIK wasn't a feature of Excel in the 1990s. You'll only see that speed up if you've working with a large enough volume of formulas. Measuring speed by UI speed alone doesn't get you very far.
All that being said, you won't find me disagreeing with the fact that desktop apps are bloated (web apps even more so). I've experienced responsive desktop apps running on a 7.14MHz CPU. The fact that we've thrown away most of the hardware improvements since the 1980s should be clear to anyone paying attention.
