The fragmentation of audiences is the norm, their centralisation is the exception

From Tim Wu’s The Master Switch pg 214:

The age of “mass media” upended by cable television was actually a period of unprecedented cultural homogeneity. Never before or since the sixty-year interval from the 1930s to the early 1990s had so many members of the same nation watched or listened to the same information at the same time. In 1956, Elvis Presley’s appearance on The Ed Sullivan Show attracted an unbelievable 83 percent of American TV households. A broadcast of the musical Cinderella in 1955 attracted 107 million viewers, nearly 60 percent of the entire U.S. population. Ken Auletta, The New Yorker’s media writer, could say as late as 1991 that “To most of us, television has always meant three institutions—CBS, NBC, and ABC. They have been our common church.” The TV networks, around the world, were probably the most powerful and centralized information system in human history. 10 Seen this way, the rise of cable and the Internet thereafter were less a revolution than a counterrevolution, a return to the more scattered pattern of American attention that once was. Before the rise of great media empires of the 1920s and 1930s, the United States, far from a united culture, was, almost by technological default, a house divided according to class, ethnicity, region, and other factors. Perhaps region most of all, for entertainment and culture were necessarily local. Early radio, before NBC, comprised hundreds of local stations, each generating its own content, however humble. Likewise, before the Hollywood studio gained ascendancy, local theaters decided for themselves what films to show. And of course before the telegraph, newspapers were necessarily local. In this sense, cable television’s undoing of the mass, or national, media culture was merely the undoing of a transient twentieth-century invention.