Take this with a shaker of salt, but according to Josh Wilding at Comicbookmovie, part of the reason Netflix has cancelled Iron Fist, Luke Cage and Daredevil has less to do with ratings than it does with the fact that Netflix wanted to decrease the length of a season.
And while that doesn’t quite seem like the entire story to me, it makes sense because anyone who’s watched the Marvel Television/Netflix shows can likely attest, at thirteen episodes then ran WAY TOO LONG, which meant that even the best seasons of any of the series tended to feel padded.
By way of compassion, Bodyguard–from the BBC, landed on Netflix last month. The first season lasted only six episodes but interestingly enough not only feels longer (in a good way) but tells a story as complete as anything as any of the Marvel/Netflix show.
I have always thought that the Marvel/Netflix shows were too long, and while I can’t speak for the other aspects of the relationship between the companies, cutting the amount of episodes that made up a season wouldn’t have been a bad thing.