So what can New York learn from a city like Kaifeng?
One lesson is the importance of sustaining a technological edge and sound economic policies. Ancient China flourished partly because of pro-growth, pro-trade policies and technological innovations like curved iron plows, printing and paper money. But then China came to scorn trade and commerce, and per capita income stagnated for 600 years.
A second lesson is the danger of hubris, for China concluded it had nothing to learn from the rest of the world – and that was the beginning of the end.
I worry about the U.S. in both regards.