I can't make up my mind what the prognosis is for China. There are 2 diametrically opposing hypotheses, both seem possible and reasonable.
One hypothesis says China will prosper and become the biggest, richest, most powerful and most advanced economy in the world. For all the obvious reasons, Chinese people work hard and save hard, they are great business creators and model workers, and there are a lot of them with access to lots of oversea Chinese people with money. Historically, China spent most of human history being the biggest, richest, most powerful and most advanced economy in the world (one could even argue that the last few hundred years, where China is not the top nation in the world, is a historical anomaly). Also, anywhere in the world there is a Chinese community, they prosper economically.
The other hypothesis says China is a time bomb waiting to implode upon itself. Again, for all the obvious reasons. China's current growth is already unsustainable on many levels. Ecologically, they are poisoning their land, air and water on a massive scale, drying up their ground water, and turning large expanses of land into deserts. Economically, a growing China is so hungry for resources that a growing China is incompatible with a growing world, China would just use up most of the world's available resources or drive up their prices to levels unsustainable for the whole world. Socially, there is a huge amount of social and economic tension waiting to blow up. Historically, social unrest and/or regime change happens pretty often, so China is no historical stranger to massive internal implosion. Except this time, it would be much worse than any other time in Chinese history, since there had never been so many people, competing for so little resources, and with the land and water so poisoned. And, oh, nuclear weapons.
What gives? What are your opinions?
My best guess is: All of the Above.
In the short term, China would be fine. By some estimates, China needs to grow by at least 6% to 7% to ward off social unrest, and the Chinese govt can and will make that happen, most likely with massive infrastructure project, which Chinese people are historically extremely good at (Two words: Great Wall).
In the medium term (10 to 30 years), there will be 2 Chinas. There will be more people in the middle class than there are people in America, and there will be a small number of very rich (most likely very corrupted) families. But the middle class will still be significantly outnumbered by the poor. For a variety of reasons (eg, the govt no longer has the resources for massive infrastructure projects), growth will slow, and many of the poor will remain poor for a longer time. At that time, both hypotheses will be true at the same time. There will be 2 Chinas. A rich, prosperous and powerful China, and a starving, poisoned China waiting to implode massively, living next to each other, maintained only by massive social and political oppression.
Long term (30+ years), most likely, very bad news. A massive and hugely dense human population is almost always, and almost everywhere, a very bad thing.