There were exceptions, one of which was the Pontiac Parisienne (some background on it is here). The Parisienne was created for the 1953 version of General Motors' Motorama, an elaborate automobile and entertainment show that usually debuted in New York City's Waldorf-Astoria hotel and then traveled to some other cities across the USA.
The Parisienne wasn't quite a concept car because it only had one feature planned for future GM cars -- a panoramic windshield. Nor was it a dream car, because its most noticeable styling feature was retrograde, landau-form roof that lacked landau irons trim. The rest of the car was a 1953 Pontiac with other, less noticeable features, the most predominant of which was the revised leading edge of the rear fender.
For the 1954 Motorama and some later Motoramas, Pontiac stylists designed futuristic -- not retro -- show cars.
Pontiacs were given new bodies for 1953. They looked like a blend of the previous 1949-52 lower bodies and greenhouses (the part above the lower edge of the windows) derived from the versions of GMs 1950-53 B and C bodies used on Oldsmobiles.
The front end is basically stock '53 Pontiac aside from the "Frenched" headlight bezels. Those four-pointed stars on the front fenders reappeared below the tailfins of 1954 Pontiacs.
The chauffeur awaits his passengers. Unfortunately for them, climbing into the back seat will be awkward because there are no rear doors.