It took me a while, but it finally dawned on me. Some rich guy moves to a place he likes, let's say a random beach in California. Only a few people around. He sets up his giga factory there and hires everyone he can. He creates a little boom in the town. So more people move there. He needs the best and brightest to make his factory work, so he pays more—just the cost of doing business. The pay goes up and up because he is making hand over fist and staying competitive with the market.
People move and settle down and buy homes near the factory. After a generation and the area around the factory booming housing prices go up. People think of homes as an investment so when new developments try to build they petition the government to block it.
So now we have the rich guy in his nice home, a little ways away the factory, in a circle from it all the supporting businesses, the executive's homes, the idea workers' homes, and then the slums used as borders between them all. Now another rich guy moves into the area and borrows some of the first rich guys money because being rich is living in a communist utopia, and repeats the process right on top of the first guy just living next door to him. And this repeats.
Till we have SF, and NYC, and DC, and so on and so on.
Now what happened when COVID hit and all the mind workers fled? The system broke down. The executives didn't have people to lord over and became useless to the rich guy so they all got fired. The mind workers with no skill got fired, and everyone with some common sense fled the city!
You can live where ever you want as long as you are in the office 9-5 Mon-Fri. You make enough money not to riot or question society. “Any serf who ran away and hid safely in a town for a year and a day was declared by law to be a free person.” sounds a lot like a non-compete.