A kung fu fighter in a disco

The problem I often have with analyses that link Popular Culture to the State Of The Nation is that the latter is taken as a given, so the former merely "reflects" it. And therefore, any answer you give is "right." E.g., during the early years of the U.S. depression, Hollywood put out lots of fun, madcap entertainments. This reflected people's desire for escapist entertainment in hard times. Whereas the pictures that dealt with poverty, unemployment, etc. were also reflecting the depression by dealing with it directly. So everything reflects the depression. Which isn't necessarily wrong, but how do you test such a thing? And therefore, how do you learn anything surprising from the movies and music that are supposedly doing the reflecting?