There's a lot to unpack here but I think I understand what you're saying.
The toxically rigid gender roles you're describing didn't get invented in the 1950's. They've existed with minor variations for centuries. The reason the 1950's look especially bad is because they were at the end of a long static period, just before the 1960's-70's when things started to get dramatically better. (Which isn't to say that there isn't still room for improvement, even today.)
Now, there were some phony social scientists claiming that these rigid gender roles were the natural order of things, just like there were phony medical researchers claiming that smoking was good for you. And they got a lot of publicity from monied interests who wanted to preserve the status quo. People who were actually doing real social science were able to figure out the problems that rigid gender roles were causing. They didn't get as much publicity as they deserved, but that's not because they were using bad methodology.
Stephen J. Gould's "The Mismeasure of Man" is a good book on the subject. He talks more about racism than sexism, but it'll still give you a good picture of the kind of dynamic that was in play.