3 points, all of which are pretty obvious, I guess:
1) The games of football and baseball have vast fundamental differences. From what I gather, the Belichick approach is to tell players to learn their playbook inside out and give 110% physical effort, and you can stick around. If not we move on to the next guy who approximates you.
2) The Patriots have Brady.
3) The Red Sox are the most successful MLB team this century, just as the Pats are the most successful NFL team. The Pats are MORE successful, inarguably, but that's tied into the fact that a team can dominate in football for a longer period.