I haven't been myself but my wife is a process engineer and had to go to China to install and train people on a new machine so this is only second hand... But one of the reasons China is so good at manufacturing is because everything is in one place (or at least clusters)... need 10,000 of an Integrated Circuit? The company that makes it is literally down the street. Need some raw materials? That's down the other str…
How is it bad for consumers (beyond the environment)?
Shipping goods does include an environmental cost which is not incorporated into the price of things - an unfortunate externality. We should have a carbon tax to properly reflect the true cost of items made and shipped so the market can choose between a locally made good and one made elsewhere.
There seems to be a popular opinion that even if the environmental cost were accounted for (carbon neutral) that it is still somehow inherently superior to make things nearby rather then trade for them from another city, state or country (especially food).