How did Prohibition affect popular culture and American society?
It created the legend of the bootlegger
The bootlegger is the famous outlaw who made money by selling liquor illegally, either smuggled alcohol from Canada or low quality alcohol very often unhealthy. The best example is certainly Gatsby who was created by Francis Scott Fizgerald in his 1925 eponymous novel which inspired numerous movie adaptations.
American Society did not see a decline in alcohol consumption, actually it led to the emergence of a Black Market and was beneficial to the Mafia and fueled crime in America.
It normalized breaking the law -
...Prohibition was basically engineered and imposed on the majority by a committed minority. In much of the country during this period, it was willfully and routinely violated.
With legal alcohol sales forbidden, a large underground economy developed to supply the demand. Much of this was run by organized crime groups, and this tended to enlarge and empower them. The mafia got a big leg up due to prohibition.