1) The city requires new physical capital to work. Its not enough to have a perfect city design. Millions of tons of matter have to be rearranged in order for that design to work. An AI by contrast only has to rearrange a small amount of matter to work.

This implies that much bolder steps can be taken. Creating a new world class city from scratch, as Dubai is attempting, is no small feat. And getting it wrong means the loss of enormous wealth. Thus even if we have some pretty good ideas on city design they will only come into being incrementally. A huge city-leap is unlikely.

2) The value from a city comes from the people living in it. The transactions cost associated with moving the entire population of a city are enormous. So, even if I built New York II that was way better than New York it is likely that it will only fill up slowly and I will only get super rich slowly. Thus the run away potential is lower.

3) While a great city increases ones potential to create greater cities, there is still the limit of human cognition. Yes, we do better thinking in cities but I am not sure if it is so much better than the thinking between cities. This implies that the intracity advantage to creating even better cities is not that great and so the first mover advantage is lessoned.

In short cities do not have the property that make the AI singularity so dangerous: cheap, strongly self-reinforcing replication.

But I think the biggest difference between cities and AI is that you don’t have to attract millions of people to your AI to make it work. Even if the analogy would work without this difference, it’s quite hard to separate this difference from your intuitions, making the analogy not too useful.

It’s a significantly shorter journey from Europe to Boston or NYC than it is to say Philly or Baltimore. And Southern ports didn’t have the human or economic capital (nor the climate) to grow like the north did.

“The Hudson river is big and carries a lot of traffic, but nowhere near as much as the Mississippi river. ”

What about 200 years ago? 100 years ago?
The Lower Mississippi watershed is a dump, mostly inhabited by people of low intelligence, and it lacks similar quantities of farmland. The Upper Mississippi and its tributaries were rendered relatively insignificant by the time that their (vast and rich) agricultural lands were put into serious use, because of rail. Shipping goods down to New Orleans would be like shipping them from New York to Greenland… what would be the point? Goods (and people) went by rail east (to New York) and west instead.

Besides, traffic through the Hudson can go *to* the Mississippi, thanks to canals. The Erie canal sealed New York’s place as the dominant east coast city, as NYC became a port to the Great Lakes watershed. (Undercutting Montreal as well for that matter) Chicago’s canal to the Mississippi continued the waterway from NYC to the Mississippi. By 1900 or so, New York and Chicago were the two great transportation centers of the nation.

“NY is a little closer to Europe, but not that much, really – maybe it was a factor in the sailing days, but those are long gone.”

Regardless of whether or not the factor disappears, the effects of it remain, with human and economic capital already put in place.

“I suspect there’s a lot of lock-in from the days before air conditioning,”

Indeed… the only reason the South has been able to grow in recent decades is air conditioning. There are other factors making it grow, but they’d all be inhibited by lack of AC.