"Even China has this legal provision in her immigration law."

What I know is that China is not an immigration country in the same way that say the UK or US is in relation to seeking "permanent leave to stay" or a "green card". Even getting a D visa, which is a precursor to permanent residence requires a detailed investigation of the invdividual. Unlike other visa categories, this type can only be applied for after the investigation. And, even if the investigation shows no impedient to the granting of permanent residence, it is not always granted. Unless one is a "special talent" or has made significant financial investment there is no clear path. The other most obvious point is that residence does not mean citizenship. In history there are a few foreigners who were granted permanent residence for their achievements in writing about Chinese history or culture or heroic deeds in times of war.

I know of only one individual, married to a Chinese national, who was granted permanent residence. And the figures provided by the Chinese don't suggest that getting permanent residence is straightforward and easy. He has been in China for 15 years and his wife works at the embassy in Beijing. he told me how tortuous the process was for him and that it took almost 2 years. Very few apply because of the red tape and I don't think they are just lazy.

If I can provide the figures I will.