Alternative history: What if China had instead implemented a two child policy in 1980?

[Agafin]

According to the latest UN population projections, Chinese population peaked this year and will undergo one of the craziest demographic collapse in the world with its population halving from 1.4 billion to 700 million in 2100 with potentially half of them being seniors. Now yes, pretty much every rich/developed country in the World will go through such a transition and it is especially pronounced in South-East Asia (Japan, South Korea, Taiwan etc,)... but the problem is that China is not yet a developed/rich country like those, it is firmly middle income with ~12k GDP per capita compared with 30k/40k for those. This demographic transition happened way too early for China and is going to be potentially more drastic here because it wasn't a natural process but was forced upon the population by the authoritarian government. They've tried to reverse course with the relaxation of the policy in 2016 and even further in 2021 but habits have permanently changed already, and China is stuck with a developed country problem while still developing.

Yet I actually think China's decision wasn't really completely unfounded at the time. Uncontrolled population growth especially for such an already populous country is a bad thing. When the population grows faster than the resources can keep up with, countries are bound to remain poor as we are seeing with Africa. And it's hard to argue that China has done better than the other similarly populated country in the World (India). So I think the biggest problem with the policy was actually with the number chosen. Imagine if instead of a one child policy, China had implemented a two china policy right away in 1980? Yes it failed in 2016 but that's because the entire chinese society had already been tailored to families having just one child (culturally but also economically when it comes to things like the cost of childcare or education). Going from 3-4 children in 1980 per woman to about 2 (which is close to replacement level) would have ensured that population doesn't grow uncontrollably but it would also have averted an inverted population pyramid. While birth rates would have probably kept dropping naturally, it would have happened more organically and would be convergent with economic development like elsewhere. China's population in such a scenario would probably peak a little higher (~1.6/1.7 billion probably) but wouldnot collapse.

Now I'm not a demographer so perhaps this is completely off base. What do you all think? Is such a policy always bound to fail no matter what?

NB: I'm not talking about the moral/ethical aspect of the policy since it's obvious that trying to impose a hard cap on the size of a family is fundamentally illiberal.

[Skill and Chance]

In theory, the Chinese government would likely be more stable today and the economy better off.  The extent to which people would voluntarily have only one child after moving to the cities would eventually be significant, though.  Unless they go authoritarian both ways in this scenario with no access to birth control until you have 2 kids?