here's the concept. If a car costs $100,000, X people can afford it. When the price drops to $50,000, X times 150% can now afford it.
Econ 101.
Yes, very Econ 101. Did you just take that this semester? You are failing to take in many OTHER factors of your simple equation.
If you drop prices, you will have more people be able to afford it. This is true, but it requires you to take into consideration your desire for either an unprotected or global market.
If the factory that MAKES that car moves overseas, all those jobs are lost, and then none of the workers can afford it, regardless of the price because their income is gone. Next, the jobs being gone, and minimum wage gone, any job will be better than starving. This is known as a labor glut, and prices on wages for what jobs are available will drop precipitously. This will force people to migrate to where there are jobs wherever they may be just like "Grapes of Wrath" with Okies moving to California to escape the Dust Bowl.
So, for your best illustration, take a look at Detroit. New cars being bought there? Barely. Glut of labor from closed plants. Those who could have fled leaving massive empty areas which the city wants to bulldoze and shut down.
The world is not so neat and clean as your econ textbook, and you need to start considering a consequence filled world where those on the other sides of boarders are not quite so sympathetic, nice or anxious to be our friends and are just waiting to take advantage of naive little innocents such as yourself.