Once the biggest movie genre in the world?
From an interview with Jonathan Nolan:
http://www.ew.com/article/2016/12/05/westworld-finale-interview
Some of my favorite movies are the Sergio Leone adaptations of the Akira Kurosawa samurai films: The Seven Samurai and The Magnificent Seven. In the period when the Western was the biggest genre in the world, the interplay between Westerns and samurai films in the domestic market in Japan was really cool. On that meta level, those two genres have this almost incestuous relationship with each other.
I knew Westerns used to be bigger than they are today, but I had no idea that they were actually the biggest genre some decades back.