Short answers, pulled from the story.
Life magazine called the 1950s the horrible decade for Hollywood because the Paramount Case ended block booking and studio ownership of theater chains. Television emerged as a powerful competitor that drew audiences away from movie theaters while audience shares reached alarmingly low levels by the mid-1960s.
Bonnie and Clyde emerged as a defining film of the New Hollywood generation in 1967. Warren Beatty produced and starred in the film while Arthur Penn directed it, and Pauline Kael wrote a positive review in October 1967 for The New Yorker.
The Panavision Panaflex camera introduced in 1972 allowed 35mm camera film to be shot in exteriors while the Steadicam arrived in 1976 making movement smoother than before. Location shooting proved cheaper since no sets needed to be built and New York City became a favorite spot for this new set of filmmakers due to its gritty atmosphere.
Heaven's Gate nearly bankrupted United Artists in 1980 marking the end of the era. They All Laughed and One from the Heart also failed at box office after studios realized importance of blockbusters advertising and control over production following Jaws and Star Wars success.
The New Hollywood generation included Steven Spielberg, John Milius, Paul Schrader, and others educated at USC, UCLA, NYU, and AFIPost-Fordist Cinema who were sometimes jokingly labeled Movie Brats or Young Turks. Thomas Schatz points out characters became plot functions beginning with mid-1970s films.