And you would be surprised how much it doesn't. Costs in SH are high, and there are a lot of millionaires in the city even if that money is mostly gray.
Keep in mind that prices in China are lower at the low end, and higher at the high end. So ya, you can buy that cheap meal for cheaper, but if you want a BMW, you have to pay 2x/3x more. I do all my high-end shopping in the states when I go back once or twice a year (and I don't own a car).
I have been to shanghai, and agree that it is not cheap.
However, other than special-case-outliers like Aspen and Davos, nowhere I have been is more expensive than Zurich.
It's like, crazy expensive.
You can live like a poor student in Poland for very cheaply but an upper/upper-middle class lifestyle (a couple of nice new luxury cars, always having the latest iphones/ipads, fancy clothing/watches/jewelry, a nice house/apartment in a good location, etc) will cost the same or more in Warsaw as in Berlin or Vienna.