Here is an interesting read about the fight between engineers, stylists, marketing, sales and management over automotive styling in Detroit in the 30's:
Auto opium: a social history of ... - Google Books
It is worthwhile starting at the beginning of the free pages and reading the whole thing.
Fordism: cheap, utilitarian, mass produced, they were forced to copy GM's style strategies, annual body changes to keep customers updating
Streamlining: at first aerodynamic, later pure style with no aero testing