"That capacity for investment seems independent of how the wealth is divided among a countries citizens."
The rest of your comment makes sense. But this last part doesn't seem right: if wealth were distributed evenly in China, then there might be no Chinese buyers for US real estate. It's only due to inequality ('how the wealth is divided') that there is a segment who can afford this.
I don't think we'd be able to infer the wealth distribution from GDP per capita, either. Total GDP tied with the Gini coefficient might tell a reasonable story. But the premise of Gini Index of 1 leaving all people too poor to invest directly in U.S. Real Estate makes sense. I'm pretty confident that China's wealth distribution is far from perfectly equal among all citizens.
The rest of your comment makes sense. But this last part doesn't seem right: if wealth were distributed evenly in China, then there might be no Chinese buyers for US real estate. It's only due to inequality ('how the wealth is divided') that there is a segment who can afford this.