Why do some Chinese people live longer than many Americans?
Every country has some people living longer than some in other countries. It is normal. Even the poorest country can have some people live longer than some in the richest country.
From the graph above, we can see that some died at birth, and some can live to the age of 110. The two curves are the year 1950 and the year 2015. If we assume life expectancy is proportional to GDP per capita and assume China’s GDP per capita in 2015 is the same as the US GDP per capita in 1950, then we can take the red curve as China’s and the blue curve as the US, for illustration purposes.
Generally, the average life expectancy of developed countries is longer than that of developing countries.
However, considering China's GDP per capita is less than one-fourth that of the US, the life expectancy of China is longer than that of many other countries about the same level of GDP per capita.