A great many people are simply not intelligent enough for more than so-called "grunt work", and I am not trying to insult them. Every nation needs jobs for every level of worker.
Mass production, mass distribution, mass consumption. We're getting to the point where there's hardly any "production" left in the USA, and our economy cannot continue forever with 2 out of 3 elements. We even import ridiculous things like SOAP, now. As long as the super-wealthy control the government (which will be forever) we aren't going to get the tariff laws we need.
Free trade = disaster.