That would only be one factor. NAFTA went into place 30 years ago. The town had an opportunity to expand, lure other companies. Other industries. Not be a company town. Sorry if your addiction to insults keeps you from seeing basic reality.
The one idea would lead someone to train for a career, get a job, buy a house, get married and start a family, and set down roots.
The other idea would lead someone to remain mobile and agile, i.e. stay single, rent, and be ready to move where the new opportunities await.
Maybe it's the pace of change. Before, someone could work for the same company his entire career because even though creative destruction was happening, it wasn't happening so fast that he had to move on. Maybe it only meant that his sons had to change professions and locations.
Maybe it's a good thing that wealth is being transferred from the West's Middle Class to the Third World's desperately poor due to unequal enforcement of environmental and labor laws. Since the fabulously rich will always be with us, it naturally follows that the great equalizing of standards of living will happen among the Middle and Lower Classes.
Adam Smith's notion that free trade allows countries to focus their efforts on creating those products and services that they are best at, and buying the rest from other countries doesn't make sense anymore. Since most wealth is generated either in factories or offices, and since central AC and heat is available across the globe, the only thing that distinguishes one country from another is the cost of the workforce and regulations. Two attributes in which poorer countries will always excel.
Since politicians are selected to help THEIR citizens, and not the citizens of the World, if tariffs are needed to even the playing field so that American workers can keep their jobs then sobeit, even if this somehow increases the overall inefficiency of "The Market".
And as far as towns not becoming "company towns". Many of the rust belt states made major efforts to lure companies in with tax breaks, etc. There were some success stories, but there were also massive failures that put those towns into even greater debt. Corporations are very nimble and can start-up, shut-down, and relocate factories and offices more quickly that established communities can respond.
Maybe we should listen to our masters at the WEF, own nothing, always have a packed suitcase at hand, be ready to relocate at a moment's notice, be single, be childless, and be happy... oh so unbelievably happy.