Namely, my prediction is that only a small overall percentage of the companies' vehicles will actually be produced within the United States. Maybe 10-20 percent. The rest will come from the companies' manufacturing facilities around the world. Mexico, South Korea, Thailand, India, Brazil, Turkey, even South Africa. Only a few high-end, niche models will truly be assembled in the U.S. such as the Corvette and some Cadillac models.
Now if you want to use the broader term "North America" then we'll see a manufacturing presence for some time to come. Canada has been a major manufacturing center for the Detroit 3 for some time, and will likely remain so. Currency fluctuations aside, Canada's single-payer health care system unloads a significant burden off the automakers that they'd have to shoulder themselves in the U.S. Likewise, Mexican industrial wages are a fraction of what they are in the U.S., and until that parity is reached (likely not in our lifetimes) it will continue to be an attractive manufacturing base.
Already, the bulk of GM's worldwide sales are outside of the U.S. That trend is likely to continue. So why duplicate platforms and tooling around the world when similar models can be efficiently produced in one location?
I'm not saying I'm necessarily keen on seeing the decimation and out-sourcing of our domestic industrial base, but the trend is clear, and it's not likely to reverse course anytime soon. The best bet for Detroit, line-workers and the automotive industry, is that the so-called "green belt" jobs being talked about by many in the incoming administration, stay within our borders.
But those jobs will likely require much higher educational levels and technical skills than many of the current UAW workers currently possess. Re-education and re-training will be mandatory. Entitlement to a high-paying job with a high-school diploma is no longer a birthright. Certainly, many entrepreneurs have succeeded with a degree from the "school of hard knocks," but the pot of gold certainly didn't land in their laps out of the sky, and the belief that it will is naive and childish. Until we as a nation get past our success entitlement mentality, and realize we might actually have to put some effort toward achieving success, we will continue to see jobs of all levels migrate elsewhere.