If you were to go back and look at each division, and only the teams in it, you'd see that every one of them is a tough place to play. The AFCE is always a dogfight, regardless of each team's won/loss record because the teams are so familiar with each other. They play each other twice a year, so there is very little in the way of surprises that show up come game day.
Sure, coaches can come and go (and they do) as well as players, but each team still develops tendencies over time that are slower to change due to player/coach transitions. It's an institutional memory like "The Patriot Way" or "The Jets Way" etc. You will get aberrations, for sure, and some slight changes here and there, but overall, it's fairly constant within each division.