The Red Sox have won four World Series in the last 15 years, more than any other organization. But they have not been able to repeat as champions in that time. In fact, a World Series winner has not been able to successfully defend the title since the New York Yankees won three in a row from 1998 through 2000.
Some teams ran into injuries, while others saw their players unable to perform at the same level. Others lost vital components to free agency, and some found their way back into the postseason, only to be denied by a better team.