Not to take away anything from Brady or Belichick since not in their control but the AFC East has been a pretty weak division compared to the others over the same period. So I’m sure that makes it easier. Jets, Phins, and Bills haven’t been able to break out and be a serious consistent threat.
Maybe that's partially due to the fact that they have to play the Patriots twice every year.
They all live under the same salary cap, and Pats get the last draft picks while Dullfins, Bills, and J-E-T-S pick near the top every year.