Conventional supply and demand economics perfectly explains both of these situations. SF has a massive under supply of housing, and restrictive zoning rules that prevent supply from increasing. China centrally funds huge amounts of developments, and many of those developments aren’t met with massive demand, so they end up with a lot of real estate that they struggle to give away in some situations.
Throw into the mix the fact that San Francisco wages are approximately 10x Chongqing wages with land at a premium as a result, and so even without zoning restrictions in SF you'd expect new development there to be expensive (and similarly even without government-subsidised overbuilding in Chinese second tier cities you'd expect rental costs to be lower than most Western cities)
This is true for SF Bay Area as well.