By 1970, many of the trends that evolved over the following decades were in place. Self-conscious art rock (for example, Pink Floyd’s album Dark Side of the Moon), singer-songwriter rock, heavy metal, and funk can all be seen as outgrowths of music at the end of the 1960s.

The decade of the 1970s was perhaps most influential, however, in its consolidation of the global business of rock. Tendencies under way in the 1960s came to exert ever-greater control over the music people heard: high-tech mass marketing; play-listed, repetitive radio stations; and aggressive promotion of “superstars” (the word itself came into common usage at this time, alongside “supertanker” and “superpower”). In 1981 a powerful new outlet emerged to promote a small and carefully selected sample of rock music: MTV began broadcasting music videos nonstop on cable.

These developments repeat, in a general way, what happened to jazz in the years around 1940. A freewheeling array of earlier musical developments came to be channeled and constrained, almost as a result of their own success.