I remember reading once that it's very hard for dumb people to write intelligent characters cause they can't figure out how a smart person thinks. It was in reference to the modern sherlock holmes film. So for modern artists, they either aren't aware of humor themselves or they believe the average person won't be able to get most stuff so they have to keep talking about it.
Somethingn I also noticed in modern comedy is that it's a very feminine way of how its presented. For instance, the constant talking is a trait I see in lots of females or weak men who have nervous ticks. It's a hyperventaliating way of getting a point across, and I feel thats the traits the writers themselves have.