Right. Some movies are too long, and they may well be lousy movies. Other movies are great, and their length is justified. Your original post stated: "Maybe it's an ego thing. Nearly every movie nowadays is about 20 -- 30 minutes too long". IMO that is an exaggerated statement. Some movies most likely are too long; others certainly are not.
I had no problem with the length of the film of In the Heights. IMO it needed its length to tell its story. Jon Chu knows what he's doing. However, the credits (as in all films today -- I believe it's required now that all contributors be credited for their role in a film) ran several minutes. The scene after the credits was unnecessary but I enjoyed it. Anyone who dislikes credits is free to leave the theater once they begin.