Let's take the star players away from those other great coaches.
Landry without Stabauch
Shula without Marino
Walsh without Young/Montana
Paul Brown without Jim Brown
Lombardi without Starr
How many Super Bowls do they win? How did Landry do without a star QB, in his last years? Shula? Walsh retired after Young and Montana.
I will put Landry at the top because he invented the defense that is prominent even today. Lambardi for innovating the power running game and Walsh for his innovative offense. Sid Gilman and Coryell as well for their innovations on offense.
But to dismiss Belichek's status as one of the best is not right. Sure he has Brady, but the year when Brady was out, he did pretty well with a QB who wasn't even a starter in College. whether you like him or not, he is one of the best, and climbing the latter every year.
And no, I am not a youngster...... I'm older than most on here.