All of those things make a very small overlap between people who need to work such low value manufacturing jobs and those who have the skills and personality to do them. In essence, we've settled in to enormous wealth and safety by cooperating with other countries, and you are proposing that we should cooperate less and be poorer.
I'm not convinced that you're wrong, but that's what you're propounding.
Update: In other words, you're asking the national level version of "why don't we move back to the land and become self sufficient and steer clear of industrial ag and make our own food?" Same answer: we like our wealth, comfort, and safety where we are, thank you very much.
Also in part because much of our leadership isn't composed of Americans working for American national interests, it's composed of humanists who perceive themselves to be global citizens and believe in a worldwide frictionless marketplace operating under a universal liberalism that incidentally control American resources.
Nothing short of global war will fix this. Enter war with China where all trade is halted, and I promise you we’ll figure out how to on-shore manufacturing in a jiffy. A terrible price, but the only solution.
Yes, let’s start a global military conflict between nuclear powers in the hope that an economic activity that’s no longer feasible maybe becomes feasible.
Not going to happen.
Why doesn't the US try to onshore critical manufacturing? This is braindead stupid behavior. Existentially risky.