This is so true: "...because they have more wealth behind them..." Construction not obvious here. "behind them" is fine. "supporting them" is fine. Also, the customers who were born in the 80s and 90s in China, because of the one-child policy, get more support and resources from their families Also, for those customers who were born in the 80s and 90s in China, because of the one-child policy, they get more support and resources from their families

Hello! This is how I would present this text: I have used brackets to show which words I have inserted and changed but the brackets should not ordinarily be there. This is so true:"...because they have more wealth behind them..."Also, for the customers (that) were born in (the) 80s and 90s in China, because of the one-child policy, they get more support and resources (for) their families Explanation: "that" is used to identify the customers - by when they were born "the" determines exactly when the customers were born "for" indicates that the support is being given to the families and is not from the families.

This is so true:"...because they have more wealth supporting them..." Also, for/as the customers were born in the 80s and 90s in China, due to the one-child policy, they get more support and resources from their families. It's only my suggestion =) Hope I helped!