The Patriots have averaged 12.5 wins per season between 2003 and 2018. The Patriots haven't just been a decent team for a long time, they've been THE best or nearly the best team (record-wise) in each NFL regular season for 16 straight years. That's incredible considering that they're playing under the same salary cap rules as the Jets, Dolphins, Bills, and every other NFL team.
I have a feeling that if the AFC North had been able to "trade out" the Patriots for any team in the NFC North in 2003, we'd probably now be talking about how "weak" the NFC North looked all these years (as the Pats dominated it every year) while raving about how "competitive" the AFC North would have been year-in and year-out. I believe that most NFL teams would have looked a lot like the Dolphins, Jets and Bills over the last 16 years if they had been stuck in a division with the Belichick/Brady Patriots.
Just because teams finish close in a division yearly and one team doesn't dominate the division every year doesn't make that division any good either. The NFC North (I'll use them again as an example) might be close most years, but that entire division has produced exactly 1 (ONE) more Superbowl victory between 2003 and 2018 than the Jets, Dolphins and Bills have over that same time.
It's not just the AFC North - the Patriots have been THAT good for THAT long.