I grew up during 11 of 13, including 8 in a row! Red was brilliant!
That said, for me, it's Belichick hands done! It's not because of the league size, but because coaching in the modern NFL is SO MUCH MORE difficult than the NBA. In a league that is heavily structured to pushing teams into the middle, Bill's accomplishments are truly phenomenal! Salary cap, yearly personnel turnover, scouting, team building, teaching football, staffing, game planning, innovation, constantly finding competitive advantage, game day execution and adjusting … these are complex, very difficult endeavors and Bill is the best ever!
I just wish he would mimic Red and light up a cigar on the sideline whenever the game is out of reach for our opponent! That would be the balls!