I used to live in China for 20 years, I can tell you this much
Not all in China are really rosy, the village my mother grow up in is in Dongguan, which is one of the most developed province in the South of China, however, not all parts of Dongguan is developed, the villain my mother was born in, still a village and people are still living a simple life.
If you compare Big City in China (like Shenzhen, Beijing, and Shanghai) to the like of US, yes, they are comparable to NYC, LA, SF or San Diego etc, on the other hand, not all of Chinese cities are like their first and second tier city, and a lot of them are still yet to develop, and those are not even comparable to third Tier US cities like Lawrence, KS, Bismarck ND, or similar cities. In fact, US does not have a definition after Second Tier City
On the other hand, while you can compare 1st tier to 1st tier between China and US, Top Tier cities in the US generally have a lower cost of living than Chinese 1st tier, except for a few exception.
And government healthcare system (like Obamacare or Medicare) does not exist in China, you only live a long healthy life if you are rich in China, if you are average income Chinese, chances are you cannot afford adequate healthcare, and they don't have Health Insurance in China, well, not until last time I was in China about 10 years ago. So I don't know where you get the fact from?