How many programmers did you need 40 years ago to write MS DOS programs? As you become more productive, more is expected of you. Instead of spending 10 days coloring pixels on the screen, now you're expected to push whole UIs in the same amount of time. Whether this is enabled by high-level languages, tools or AI is irrelevant.

What am I to be productive on? The bottleneck now is finding a business idea that's viable.

I wonder if we need teams generating dozens of UIs or whatever every day though. There may (or may not) be a limit to how much value-adding work is available to do, or at least diminishing returns that no longer justify high salaries.

YEs we do - your point that there might be too many is valid, but a modern UI when done right is much more accessible to the "common man" than a MSDos and so all the time those teams put in is more than made up for in all the time you saving not having to teach all the people who will use the program and thus we need far more teams than in the MSDos days when we couldn't make a good UI in the first place.