The explanation I heard was more about capital controls. A fairly well-off middle class Chinese citizen cannot plan for retirement by buying into an S&P 500 fund and waiting three decades. Chinese bonds have negative real rates. And the fate of the stock prices of domestic Chinese companies are subject to the vagarities of the shifting whims of the Chinese government. Where else are they going to put their money? An apartment that sits there empty for two decades and then gets sold looks quite attractive in that context.