Étienne Fortier-Dubois

Why did this happen? The simple explanation is the Mongol conquest. However, China recovered from that disaster under the Ming by most measures, and the institutions created under the Song were still extant when the Mongols were expelled in 1368.

the Song came to depend increasingly on taxes on trade and so systematically encouraged it.

So, that shifts under the Song policy to a policy of "hey maybe let's not tax the pants off of the peasant farmers, and instead try something craazy." That "crazy" idea is to tax trade - both internal & with foreign entities.

The Yuan follow up on this by being super into global trade, commerce, and cultural exchange (whether anyone else wants to or not)... to the point where their shoddy economic policies, climate change, and the Black Death burn out the Chinese economy and throw the whole region in chaos (again)

Then the Ming comes in, saying "screw that, we're going b... See more

This tremendous growth came about, in significant part, because of a rather revolutionary reform to the taxation policies of the realm.

China and Europe are different in many ways, but one is that after the Mongol conquest in the 12th century, China remains a unified empire run by a single Mandarin bureaucracy.