Serving as the culmination of the past decade of the Marvel Cinematic Universe, AVENGERS: INFINITY WAR was already stocked full of more characters than it knew what to do with, but at one time, there was talk of adding even more in the form of the heroes from the Netflix Marvel shows. During a Collider-hosted screening of INFINITY WAR, directors Joe and Anthony Russo took part in an extended Q&A where they explained that they did have conversations about including the Defenders in the film.
Yes, of course we talked about all that stuff but you can see how many character there are in the film. It’s very difficult when you’ve got shows that are being written when you’re also trying to create movies that are not happening on the same, just from a production standpoint, at the same time that the shows are being produced. It’s impossible for us to correlate story between three or four other marvel films that we’re borrowing characters from and then to add the TV shows in on top of it. It just becomes an experiment that would break. We felt that the best way to tell the story was to stay with the Marvel Cinematic Universe.
Putting AVENGERS: INFINITY WAR together was already an incredibly complicated process, so you can see why the Russo's elected not to juggle the schedules of multiple TV shows on top of that. Who knows whether or not the heroes of the Netflix shows will ever get the chance to shine on the big-screen, but as INFINITY WAR barely had time for some of the MCU's biggest characters, it was probably a good call that they weren't jammed into the film. Are you still hoping to see Daredevil, Luke Cage, Jessica Jones, and Iron Fist turn up in a MCU movie one of these days?