... this part of Allen Sanderson's essay on incentives:

For example, given that the Chicago Bears can sell out Soldier Field constantly, and the National Football League (NFL) shares its television revenues equally across members of the cartel, it is not surprising that the owner of the Bears is willing to do without a costly high-quality quarterback—payroll would rise but any effect on revenues would be shared with all the other teams.

True enough, but what if a better quarterback (which means almost anyone since the imcumbent is Rex Grossman) allowed the Bears to charge higher ticket prices while selling out Soldier Field? This source indicates that stadium "gate" revenue is spilt 60-40 between the home and visiting teams, respectively. Thus, even a team could reap a large, though not complete, share of revenue generated by a QB upgrade.