Vintage Cars: Rear doors on older cars, conventional doors, expertise thanks

Question
Hi, I noticed in a recent 40s movie and remember that rear doors on cars used to open backwards from the center post, rather than parallel to the front ones as they now do.  Questions:  When and why was the change made? (I can think only for esthetic and maybe safety reasons.)  Did all US models and foreign cars open the same way?  I'm really curious and would appeciate your expertise.  Thanks, Jim

Answer
Hi Jim,

Interesting question.  I don't think there's one complete answer, but I'd guess the factors in the demise of this style of car would be a) safety b) cost of manufacture and limitations of style and c) people's preference for easier entry and exit using conventional doors.

best

Joe