30 years ago, the purpose of One-Child policy is to reduce billion of population to 0.6~0.5 billion in China ... recent years new policy is new Chinese family which the wife or husband come from the One-Child family can have two babies.
I come from the One-Child family, i support two babies for every Chinese family but not more. I hate a crowd & poor China, welcome a comfortable & high-quality China.
You will then have to choose between being high quality, or perhaps giving up a little bit of quality for being huge.
Quality of life by itself means nada. No body in the world cares much about Denmark, or Liechtenstein. Do they?
America had a policy earlier of US vs the rest. It always aimed at creating capacities where it is bigger than the rest of the world. It still is today in terms of military might.
Than it came to a system of US + hard core allies vs the rest. And today it does hold that true.
China must have an economy that has a 35% share in the world economy to truly make a mark as big as US in 20th century.
China and U.S almost have the same land size, but China has 1.3billion ppl and U.S only has 1/4 ppl ... do u see the U.S collaped ?
US population is more dispersed. Not that of China.
Also, US is surrounded either by vast oceans, or by relatively small states. Canada is lucky that it exists. Mexico is also too small.
With China, you have loads of surrounding states, with loads of claims. So yes, if you can demographically subsume your west, than perhaps we can talk, but right now, those two places are hardly settled.
Israel has actually converted vast tracts of desert to farming land. It can be done. It's all about will.
Remember, the biggest strength of China, as you yourself say is its people. Why do you want to decrease that strength?