Well, at least they have systems that really work.
In MLB, teams dont have salary cap, but teams who spend more than the agreed threshold will have to share their revenues to the whole league. So the KCs and the Milawaukees of the world are thanking the Yanks, Dodgers and Angels for some of their revenues.
In the NBA, they have a working salary cap policy, and those who spend more than the cap pay luxury tax dollar for dollar in excess of the cap. The tax are divided and are given to the smaller market teams. So Jordan and his Bobcats (err Hornets pala) are really grateful to Dolan and his Knicks.
NFL is the model of parity in the US pro sports scene. They have a very structured and very hard salary cap policy. Small market teams can actually compete with the bigs. I bet nobody here in InterBasket has ever been to Green Bay Wisconsin. But you see towns like this being very competitive, and has no problem signing high profile players. NYC has 2 teams and both are irrelevant coming in to the 2nd half of this season. Los Angeles, the 2nd largest TV market in the US, doesnt even have a team.