Well, I think (and many of my fellow engineers as well), that we were making good progress in UI design and abstractions until AJAX and the modern web came about. I've said this before and I will say it again: the web has brought modern software development practices back in time by at least 20 years. Everything had to be reinvented: usability, interaction patterns, accessibility, quality control, component-based GUI design, supportability and so much more.

And in many ways we have gone backwards. Interaction patterns vary wildly from site to site. Most don't have undo/redo functionality. A failure of one component often means a failure of the whole. Accessibility on the web is terribly poor for the vision impaired. Interaction response time has gone up, not down even though our machines have many orders of magnitude more power than the 90's. Most websites cannot be properly maintained due to lack of coding standards and abidance of best-practices.

Ok, just an old fart rant. Don't get me wrong: I think we have made leaps of progress when it comes to distributed computing, machine learning and mobile application development. The web, however, has turned into a huge dumpster fire.