I don't buy it. Curvy cars were not some high end European flirtation in the 60s. Pretty much all cars in the "old days" were rounded. Random examples:
http://en.wikipedia.org/wiki/Chevrolet_Deluxe
http://en.wikipedia.org/wiki/Studebaker_Lark
http://en.wikipedia.org/wiki/Packard_180
Why publish an article whose premise is so obviously wrong?