I don't think it can be explained very simply. It was a combination
of World trade treaties, which divvy up the spheres of influence. Also the
local subsidies in terms of loans, tax abatements, and interest rates.
Pollution laws and labor union issues and advantages. Small dealerships forced to close. Loss of Pontiac, Oldsmobile and Saturn. Surviving dealers forced to build new expensive showrooms. International trade in intellectual property. Out-sourcing. End of owner-maintenance capabilities; creation of computer-controlled everything. Generational prejudice against rust-belt industry.

Do You own a car built by Durant? yes