The NFL has played 32 games during the regular season so far, through two weeks of play. And, strikingly, football still pretty much looks the same that it did the year before, and the year before that, and the year before that, and on and on, through every rule change that we constantly see get passed.
The league passed a new rule that outlaws hitting an opponent by lowering their helmet. The assumption by many was that this was going to radically change the way the game was played. Frankly, this was something that some coaches even believed, and they were worried.