How has the media's depiction of organized crime changed over time?

According to Klaus von Lampe, the term "organized crime" first developed in the  early 1920s, after the founding of the Chicago Crime Commission in 1919. The commission, organized by civic leaders, focused on reforming the criminal justice system and conditions in society that gave rise to crime. The public was seen as too soft on criminals, and the criminal justice system was seen as inept in persecuting criminals. In the mid 1920s and into the Depression, the focus on organized crime turned to gangsters and syndicates who, like Al Capone, who was deemed the number one "Public Enemy." While earlier media coverage of organized crime focused on reforming local conditions to reduce crime, the media in the 1920s turned to vilifying gangsters, who became the focus of law enforcement nationwide.
By the 1950s, the Kefauver Commission under Estes Kefauver targeted organized crime nationwide and referred to its target as the "mafia" (also sometimes known as the "mob"). The media began to focus attention on Italian-Americans, who were seen as the main participants in the mafia. The term "organized crime" began to gain an ethnic connotation in the national media. By the late 1950s and beyond, the media's and the popular conception of organized crime and the Italian-American mafia became synonymous, popularized by such books and movies as The Godfather. Although organized crime had many different forms, the media began to use the term as a way to refer to the Italian-American mafia. 
 
Sources:
"The Concept of Organized Crime in Historical Perspective" by Klaus von Lampe. Paper presented at the international conference "Crime organisé international: Mythe, pouvoir, profit...", sponsored by the Institut de recherches interdisciplinaires, Université de Lausanne, Switzerland, 6 October 1999.
Leiva, A. & Bright, D.A. Trends Organ Crim (2015) 18: 311. doi:10.1007/s12117-015-9251-2.