While it is true that the Yankees have won far more World Series titles than any other team in Major League history (27 titles, next highest total is St. Louis with 10), and that team salary is correlated with winning percentage, what does the current climate of the playoffs look like in comparison to other major sports? Specifically, since the advent of the wild card in 1995, how has the playoff picture changed year to year and how many different teams have won a championship in that time period? There is an interesting twist to this, as only 8/30 MLB teams qualify for the playoffs, while 16/30 NBA/NHL teams qualify. Obviously, there is a better chance of having a larger number of different teams in the playoffs from year to year in those leagues. To account for this, I found the total percentage of different teams each year. Also, I took the change in teams from 2004 to 2006 and simply skipped the 2005 NHL lockout season. This is what I found:
MLB has averaged nearly 4 different teams in the postseason when compared with the previous year. Stated differently, in the wild card era, there has been a nearly 50% turnover rate for teams in the playoffs year to year. Over this same length of time, the NBA has averaged 3.7 different teams, or 23% turnover rate and the NHL has averaged 4 different teams , or 25% turnover rate.
Ok, but what about championships? How many different teams have won the respective championship in each sport over this 15 year time-frame?
According to this measure of parity, over the past 15 years, the MLB has had the same number of different champions as the NHL (2005 strike counted in the total) and 2 more than the NBA.
In conclusion, it is very difficult to say that there is no parity in the MLB, or even that there is less parity in the MLB than in the NBA or NHL.