An interesting article with some good points. One thing I didn't see mentioned, that I've noticed as an old guy, is that a given joke isn't necessarily funny a second time, and a lot of movies and shows use jokes that have been around a while. Probably nobody laughed when they read the "boy are my arms tired" joke used as an example in the article. That joke has been around since the 40s, and the article uses it because it's so familiar to so many people. It was probably funny once, but now it's a cliche.
So if I go to a movie and the jokes are variants of ones I've seen or heard a bunch of times, I'm probably not going to laugh, and that doesn't mean I've lost my sense of humor.