Far from my area of expertise, but my guess is because people can swallow lack of forward progress way better than they swallow going backwards. The current trade with China started back under Nixon, and Americans have gotten used to so many ultra cheap Chinese goods. I try to avoid products from China, and for some things it’s really hard, and it usually means paying double the price. If we cut off that trade or raised the tarrifs a lot, the price of so many things works skyrocket and people wouldn’t stand for it.