COD Dead?

Call of Duty is definitely a generational game. By that, I mean that the game is always targeted to a particular age group and that particular age group will always purchase the game.
That being said, I think the game began a slow death a long time ago. There was a pretty hard cut-off for game quality once Ghosts was released (in my opinion, some may disagree). I personally thought World War II and Black Ops III were decent games, but Infinite Warfare was a trashpile and Black Ops 4 has been an enormous letdown. Call of Duty games got progressively better all the way up until around Modern Warfare 3 or maybe earlier, and then the decline began.