The top-tier luxury car has evolved along different lines than other cars. The assembly line revolutionized mainstream car making, and made the automobile affordable for millions of people. But, for a car costing at least ten times what a Model T cost, a different approach was needed. With really high end luxury cars made before WWII, you would generally buy only a chassis from the actual automaker, then you would have it sent to a coachbuilder to have a body made to your particular specifications. Luxury car companies also tended to be more local businesses than mainstream car companies, as people liked to be close enough to oversee in some capacity the building of their car.