Less than 50 years, almost everybody worked in manufacturing. As manufacturing productivity improved, both through automation and through trade, people were freed up to work in service industries -- from flipping hamburgers to computer software to making movies.
Fifty years from now, people will look back and marvel at how many people used to work in what we now call services, most of which will be automated by then. We don't know what people will be doing for a living in fifty years, but we do know that people will always have needs and that other people will find it in their interest to satisfy those needs.
Preventing free trade may benefit some individuals or groups, but facilitating free trade will bring greater benefits to more people. To compete we will have to actually educate our children -- and ourselves, as adults -- but that is a problem to be solved not by building up trade barriers but by breaking down mental barriers.
First, we are not in a free trade envirornment. free trade would mean that US produced goods and services would be allowed to freely compete in foreign markets as well as foreign goods and services being allowed to compete in american markets. Further, government subsidies for offshore investing would not exist.
As to trade barriers the USA developed as the foremost manufacturing economy with trade barriers in place that is behind protective tarriffs for manufacturing. That is historical fact. Unless and until you can prove your case I would suggest you not comment about that of which you lack knowledge.
Do you bother to think about what you write first? Yes Americans moved more toward manufacturing as agricultural productivity improved, but we still grow the food here in the good ole US of A(even though greedy Anti-Americans decide Illegals are prefered over Americans for this type of work). Unlike manufacturing and high tech jobs which have been outsourced/moved to other countries.
Thankfully we live in the best place for agricultural production, because if these greedy SOB's even thought for a minute they could save a buck by growing everything in another country, they would kill agriculture in the US in a minute.