What I'm saying is this: Western countries have experienced the problems that China has experienced in the past, but they have reached the status of a developed country without decreasing their population.
So which Western country has experienced traffic so bad that you can only drive your car 3 days a week and you have to wait 6 years to buy one at all? Can you give an example? This here shows me that China is overcrowded. Western nations are currently experiencing an issue where young people cannot afford housing and this is causing a drop in birth rate but with much lower population density, the problem is just not as severe as in China.
In order to become a developed country, it's not about reducing the population, it's about giving importance to technology and spreading it to the base. China has the resources and productivity to do this with the current population as well.
It's also not about increasing population. It's about increasing education, increasing the educated elite in STEM, which takes high per capita resources. Total population will be sorted out by the mechanisms of the ecosystem you create.
As I understand it, you are arguing that the population will eventually fall into balance and should not be interfered with.
Not necessarily that it cannot be interfered with but that adjustments have to be made by adjusting the ecosystem itself and that effect will rebalance the population to a higher or lower number.
But the most critical point I am making is that maintenance or even near maintenance of the current population numbers is not crucial to China's success and population decline, up to a certain point, which we are well within, is natural in this case and can be more than outweighed by increases to the educated elite, allowing innovation to increase rather than decline with the general population.
What if it doesn't happenCan
Then we panic!! We tell Chinese people we'll all go extinct if we see a little bit of decline! We force women to have as many kids as possible!! LOLOL
Yes, I guarantee it. Every system will find a balance. I guarantee it and as a Chinese person, I bet my life and future on my guarantee.
What if the one-child policy has upset the balance. What if this low trend of marriage and childbearing in society continues.
Balances are upset and then reset all the time. If this low trend continues, then it is because the ecosystem is still calling for less. If you want more, then the ecosystem has to be changed and that will naturally cause birth to increase again. What does your what-if question ask? Continues to when, to a population that is what? Because it will continue for the time being and it will not be a problem but it cannot drag out for, say, a century, which will be a problem.
With the low youth population rate that will occur in the future, it will be very difficult to keep even the balance, let alone increase the population.
What is low? It's still basically the highest in the world. You saying that China's low population is in jeopardy sounds funny to every country other than India. What are these countries all going to do with less young people than China? All die out because they can't increase the population because they have fewer youths than China? There are currently many countries with much much fewer young people than China and they can increase the population. China can easily do it too, if the environment is right.
Therefore, the most logical way is for the government to try to increase marriage and birth rates as soon as possible.
There are already policies for that but they don't amount to the panic you seem to have about China's future dependent on the population staying the same or nearly the same as now.