36 years of government policy with harsh penalties for having more than one child doesn’t disappear quickly (1979-2015). They’ve trained two generations not to have kids, and the looming global climate disaster affects everyone worldwide. And while I haven’t looked into it, I think it’s a safe bet that in large Chinese cities the cost of living has also outpaced wages, like in nearly every other major city in the world. None of that is conducive to wanting to have kids.