Los Angeles in 1974 exerted more influence over popular culture than any other city in America. In movies, music and television, the early 1970s marked a towering creative peak in Los Angeles that transformed each of those industries. The “new wave” that revitalized Hollywood, the smooth Southern California sound that ruled the album charts and radio airwaves, the torrent of groundbreaking comedies that brought new sophistication and provocation to television’s prime time: all of this emerged from Los Angeles. Working just blocks from each other in film, recording and television studios…