Legendary British actor, David Niven, said in an interview with Michael Parkinson that in the old days of Hollywood (30s), they had to resort to publicity stunts because there was no other way to stir up interest. They didn't have TV networks and certainly no internet or social media. So, for example, they trained 150 parrots to say the title of a film and placed them all around Los Angeles to gain publicity.
People go to the theater to feel like they are a part of something bigger. That is ultimately what we as humans crave. So, the marketing and development of a film should convey the grandiosity and cultural importance of the film. You're not just going to the theater, you're going to THIS MOVIE. When you see Star Wars VII or VIII, you're not just seeing a movie with big movie stars. You are seeing history in the making. You've dreamed, you've waited for a decade and you never thought it would happen... and now it has.
A film like Interstellar benefits from a theatrical release because of the visual effects, cinematography and scope of the film, but a successful film from the past like When Harry Met Sally would not necessarily benefit because ultimately it is about the story and not the image. However, if a genre/generation defining romantic comedy came out today, it would probably have a great theatrical release because it would be a cultural statement, a moment in our culture's history. Plus couples could go with other couples. There is something very magical about sitting with strangers in a dark room. Your consciousness becomes close to one and your enthusiasm builds. That is also why a great comedy kills in theaters; hearing others laugh at the same joke is fun.
Modern marketing is going to have to go beyond posters, trailers and social media influencers. Movies need to be events in the life of an audience. It is not just about the story on the screen; it is also about the story around the screen. Write a great scene in the life of Americans, in the history of humanity.