To John's point about fragmenting viewership, I never heard of Yellowstone (the show) before your post. No clue it existed.
TWD should be studied, if not already, for one specific reason. So many people, myself included, tuned out at the same time - when Negan killed two main characters. That was the end of the season as I recall and we just never cared enough to start watching again, and it wasn't like Glen was some massive fan favorite of mine either. I think it was the brutality of the scene, or just exhaustion about the whole thing, and I was one paying per episode on Monday mornings on Amazon (which I never do). At any rate, I will pop in to random threads like this on TWD and its amazing to see how many people say the same thing about when they stopped watching.