Show biz is most appropriately understood as entertainment, not culture. A movie is no more significant than an athletic event or video game. At best they are lagging indicators of culture, not drivers. To believe otherwise is to buy into the entertainment world's inflated sense of self-importance and desperate need to be taken seriously, against a tsunami of argument to the contrary.
Is literature culture? Is music? Then so is film. Movies have decisively shaped the culture of the last century.