When cars had wheelbases which were long enough to allow for an ample 2-dr door length and the B-pillar could be moved rearward from the front seat location, to allow for easier entry into the rear seat, then 2-dr vehicles were viable. Especially for people who were more limber in body movements.
2-drs were "sporty", as all sports cars were 2-drs. Then, in the early 1960s, 2-dr roof lines became more sleek for better NASCAR aerodynamics. GM made their 2-dr hardtop roof lines mimic a convertible's roof line. A plus for many, it seems, as a convertible was a glamorous car to have, back then. Racy, sports, and sexy . . . 2-drs were, one way or another.
When the downsizing of the later 1970s happened, cars became shorter and narrower. Most larger 2-drs were not viable for anything of a family nature, typically. Which means we now have generations of people who grew up with smaller 4-dr cars. No big deal to them.
To me, a 2-dr hardtop will always be worth more money than any pillared sedan. 2-dr hardtops, 4-dr hardtops, convertibles, and some station wagons will always be worth more than a 4-dr sedan, or especially a 2-dr sedan. How much of a difference could well be determined by the size and brand of the car, plus its styling in each body style. 4-dr sedans were the more common body style, which made the others more exclusive in nature, by comparison.
Beauty if in the eyes of the beholder. Even better if the beholder has money to spend!
Just some thoughts,
CBODY67