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.
Which shows that the quality isn't fading at all. There've always been teams that were collections of individuals, and those teams are rarely the winners, they might win a few games, might even make it to the playoffs, but eventually they will be over come by a team that is a team. Dallas is a team obsessed with individual success from the coach down, and they haven't gotten near a Superbowl and probably won't. Meanwhile the Pats are a team that's obsessed with being a team (first team to refuse individual introductions in the SB) and they won 3 SBs out of 4.