I could add a few
Farming technology. Ancient chinese farming technology is about as advance as post industrial revolution in Europe. Chinese farm all years. Europeans do not have good irrigation system.
Ancient chinese cultures measure prosperity by population growth. The idea is if you govern well, people will come to you (like people flocking US and capital flocking Asia).
This measurement of prosperity is actually quite natural. Ask any biologist what success means for an organism and it'll say something along reproductive success.
Kong Fu Chu beliefs that having children and grand children is good. In fact, it's something along obligation. Your parents create you so you create grand children for that.
Not much sexual restriction. Concubinage is okay. Prostitution is okay. Polygamy is okay. In western civilization, no matter how rich you are you only have 2.5 children.
In China the rich have as many children as they can afford.
Unlike Arab with strong anti sex outside marriage laws, getting mates and producing offspring may be relatively more peaceful and apolitical in China. It's more economical rather than political.
Just get rich, and grab concubines/wives. That's the chinese way to reproductive success it seems. No monogamy terms. No religion telling you it's wrong.
In Arab, you got to fight first and control the religion before you can enjoy such package. If you're a member of minority religion like Christianity, then tough. Sex is too politicized in both Arab and in Europe. In China, reproductive success is pretty much market based.
So in China people can produce more offspring by getting rich. That tend to match number of offspring with food that leads to higher number of children reaching reproductive age that leads to more population.
In europe, the poorest actually make more children and that is something I am still puzzled till now.