I don't know if you're baiting for a conspiracy, but I'd go as far as to say top level politics are to blame in both countries, albeit more directly in the case of China.
America's ghost towns were once thriving and now are deserted. China's ghost cities are relatively new and have never thrived before; they are just symptoms of a huge real estate bubble.
China overbuilds way too much, even in thriving cities like Shanghai and Beijing will you find almost completely deserted shopping malls.
I only observed that America and China both arrived at the same end result independently - ghost cities. I am not saying that they followed the same approaches, or took the same time.