The U.S. has invested trillions of dollars building an infrastructure that has led its citizens to being some of the best-educated and most-productive in the world. Those citizens are capable of doing higher-value work. Should they do that low-value work when it can be easily and eagerly performed by other countries where the populace hasn't benefitted from such an infrastructure investment? Thereby raising the standard of living for all the parties involved? That's the economists' argument. Moreover the late 19th and the first half of the 20th centuries taught us that focusing on the nation-state leads to widespread warfare. Better to have those nation-states in economic cooperation that leads to peace than economic competition that leads to war.
I'm not saying you're wrong, but I am saying you need to really think through why and how we got here when considering our next steps. You're going to need to address how doing what we did before won't lead to the same problems we experienced before. I suspect you're not going to be able to do that, but I'm willing to be shown to be wrong.