True, the three teams with the most titles (Boston, L.A., and the Chicago Bulls) show up with amazing consistency. One of those teams has won the title 61 percent of the time going back to 1947.
Why such dominance? All three soccer-mad nations produce excellent players through well-developed networks that bring promising young players in contact with expert coaches. They play against challenging competition. And the World Cup itself has no restrictions or rules that try to help weaker national teams at the expense of better ones.
More balance in America?
The NBA is supposed to be different. For decades, the teams with the worst records have had first picks in the NBA draft. The league also has a salary cap designed to keep richer teams from outspending poorer ones in the search for talented players.
But since the 1984-85 season, when the modern cap was instituted, the three top teams (L.A., Chicago, and the San Antonio Spurs) have been even more dominating than in earlier NBA history. One of them has won the championship 69 percent of the time.
Take professional football. One of the three teams (the Pittsburgh Steelers, Dallas Cowboys, or San Francisco Forty-Niners) has won the Super Bowl 36 percent of the time. Since the league instituted a hard salary cap (with fewer loopholes than the NBA), has that percentage declined?
No, it's climbed to 44 percent.
Baseball has resisted a salary cap and instituted instead a luxury tax on teams that spend more than a certain amount on players. Since it took effect only in 2003, it's too soon to judge its effect using this measure. But don't hold your breath.
"Some people say [Baseball Commissioner] Bud Selig's worst nightware is that the Yankees and the Los Angeles Dodgers would be in the World Series every year," says Mr. Sanderson. "I think his worst nightmare would be the Kansas City Royals and Cincinnati Reds in the World Series every year. Deep down, they need the major markets."
Is it just talent?
Of course, there are many ways to measure dominance. Using championships won by the top three teams makes it easy to draw comparisons among sports. One explanation for this unusual dominance is pure talent.
Maybe these teams have stumbled on a player or combination of players and coaches who find a way to win year after year.
If it is all due to talent, then individual sports like tennis should produce champions with equal dominance.
Indeed, the three top men's singles players in terms of Grand Slam titles (Roger Federer, Pete Sampras, and Roy Emerson), have won 21 percent of all the slam tournaments played since 1919. That's very good but lower than even US football. And even top tennis pros get a built-in advantage.
Tennis versus golf
Because of pro tennis's seeding system, top players don't face the toughest opponents until the latter rounds of a tournament, Sanderson points out. Pro golf is one of the few major sports where champions have to beat the entire field.
How well to the top golfers do?
The three top men's players in terms of wins at the majors (Jack Nicklaus, Tiger Woods, and Walter Hagen) have won a combined 43 titles since 1914, when Mr. Hagen won his first major tournament. That's 13 percent of all the titles, which is impressive.
But it's nowhere near as dominating as the top teams have been in major league sports or the World Cup.
Maybe competitive balance isn't so important to sports leagues after all.