Building a vehicle starts with years of planning, thousands of global suppliers and available workers, millions of square feet of factory space, and billions of dollars in capital expenditures.  It takes years to bring a new factory on-line, assuming you have the people and engineering staff to run the factory.  It is not something that companies do quickly or on a whim.  There are financial and logistical concerns that must be taken into consideration – often over a large number of years.  These are the logistics of the American auto industry.