Still, it’s rare that movies longer than three hours are released, so as Shyamalan mentioned, eventually there came a point where he started to tighten Glass up.
Plus, one also has to account for people checking out Glass who haven’t necessarily seen Unbreakable or Split.
Now the movie is a little over two hours, which is a more digestible runtime for the average moviegoer.
Because Unbreakable and Split are set in the same world, it’s understandable that M. Night Shyamalan wanted to dedicate plenty of time to ensure that fans of one or both of those movies would be properly caught up.