I understand your remarks Jed, now, several things.
For example an old city as Paris, is organized as a fractal, with a real center, so as you well explained, difficult to carry all workers in the same time in a small working area.
However we have city trains (RER) to carry people from external corona up to the center. We should remove these dirty trains to recover lines then adding way for self car/bus as explained earlier.
it's different in US because Cities are organized as a network better to circulate.
Also, don't minimize how a self car network will be faster because no stop needed, no traffic light needed.
Jurg's is doing an interesting model with his donuts atom.. Now, i'm very angry about him because never he was able to explain why nature needs this kind of shape..
Now, if we try a comparison with these 2 topics, we well understand if too many "things"( energy) have to stay in the same place, it will better to enlarge this place and leave empty the center..
This is the case of Paris, for example, where most of people are moving for work inside 2 separated points of the external corona ( banlieue).
About US side, we should need a road reorganization as done Baron Haussman at Paris.
To finish about Jurg's donuts he should ask himself to better understand his donuts shape represents only a truth at a certain point in the universe history... Probably this shape evolved with time, because rules evolved too..