He's saying the "style" discussion died down in the 70's, not the 20's. He gave the twenties as a reference point for the beginning of the discussion about film. And from then up through the late 60's/early 70's it was part of the conversation. I think it fell by the wayside for a few reasons: 1. The rise of newspaper criticism. The film reviewer's charge is to tell the audience if they will like a film or not. Generally speaking, plot and theme are more accesible to the masses compared to discussions of editing and mise-en-scene. So, they keep it simple. Sad thing is, most people don't read the reviews anyway, they just look for the quantification (thumbs up, 2.5 stars, etc). Those who read the reviews are probably more likely to understand/appreciate a more holistic summation. 2. Film had just become an academic discipline and to get universities and other academics to take it seriously, they probably felt a need to show why film was "important" beyond aesthetic appreciation. The textual analysis approach resonated with students and professors alike as it allowed them a catalyst for expositing their ideas on a very turbulent society with the ability to cite examples through a work of art. 3. That was an era of change in the film world, particularly in Hollywood. Independent filmmakers were emerging, the old masters (Hitchcock, Welles, Ford, Hawks, Wise, etc) were wrapping up their careers and the new guard (Spielberg, Scorsese, Allen, Coppola, Altman, etc) were taking over and the films they were making (MASH, The Godfather, Mean Streets, Easy Rider, etc) were just as intriguing socially as they were cinematically, and tended to have more to say than most Hollywood films in the decades prior. Also, they were attempting to create their own cinematic style. Influenced by French New Wave, Italian Neo-Realists, classic Japanese cinema, in addition to the Hollywood legends, they were creating a whole new "film grammar". The well-defined notions of classical Hollywood style were being subverted and the academics probably found their students about as well-equipped as they were to discuss it, if not more so, because they were closer to the mind-set and attitudes of the filmmakers putting them out. These were the students of the legends and they were doing new things. This is where Bordwell is making his point. It was an exciting time to be a student of film, but whatever reason, the academy wasn't as excited about the growth stylistically as they were the growth thematically. that's the way i see it now anyway. let me think about it and i might refine/amend this later.