Places that used to do this in the U.S. have left major scars and real human impact. The lack of regulation and enforcement mean they are causing the same (or worse thanks to scale + neglect) in China.
None of the things I listed have to have a large environmental impact. We have huge warehouses and same-day logistics in the US, they're just for consumer goods. Making PCBs or coating electrodes or working metal can all be very low-impact processes. Shenzhen isn't Bhutan but it certainly isn't a chemical waste pit. Most Chinese pollution comes from coal or resource extraction, not manufacturing.
Like how people don't get married because divorce is such a big risk. Or people don't drive too fast because it's not speed that kills but the sudden stop.