The NFL teams that win have that quality. Actually most of the players in the NFL already have that quality whether their team wins or loses, the majority of players on the field at any given time are there to give and take physical punishment to allow others to succeed, no flashy receiver to could ever receive a TD pass if the o-line wasn't bashing people to protect the QB. Just had another shining example of it last weekend when the Steelers got their rings, Dan Rooney felt the ring should only have one Lombardi trophy represented on the ring to allow the current team's accomplishment to stand alone, the players he consulted wanted the other four Lombardis represented because they're a part of Steeler history and the players wanted to join that history and not merely stand alone.
A very good point, but that quality is fading quickly over the years. When Dallas was at it's best, the team was a team. Now the Cowboys are nothing more than a few team members surrounded by individuals (especially since aquiring T.O.) that the Tuna brought on board in a feeble attempt to get to another Superbowl so he can retire again. Without instituting a team mentality, he'll never get there.