[Noumenon]

The Chinese didn’t help themselves by buring their libraries over and over again. Imagine the loss of Alexandria repeated with the transition of virtually every dynasty.

[Nikas777]

Great point - I would add the Chinese banning exploration of the outside world because the Chinese assumed they knew all that needed to be known. So civilizational collapses can also be self induced.

China sent a world spanning fleet out in 1421 (may or may not have reached American but for sure went to Africa) and on their return their emperor ordered the fleet burned and trade with the outside world banned.