Because once 99% of the population lose the opportunity to at least learn a skill that they are good at, and (Importantly!!) for which they have some aptitude over others, and apply it, then they will face an existence of very little meaning. Like it or not, people want to be distinguishable from others, and if everyone can do everything with AI, then that disappears.
Techies don't like to admit it because they are at the top, but through AI, they are creating their own bubble world with their little toys that will act through the immense power of AI as an oligarchy that rules the listless and depressed masses.
A rather contemptible existence, in my opinion.
If I could have it read more of my project in a single gulp and produce the 10-1000 lines of code I want in a few seconds, I wouldn't need it to go off and write the thousands of lines on its own in the background. But because even trivial changes can take minutes by the time it slurps up the right context and futzes with the linter and types, that ideal pair programmer loop is less attractive.