We don't need the raw material extraction and that's why I didn't mention it in my comment. Raw material extraction doesn't happen in Shenzhen and for some materials it doesn't even happen in China. You can get a shipload of cheap sodium sent wherever you are. All you need is a few companies to store a bit so it's readily available.

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.

It's the sudden shutdown that gets you.

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.