The Marines are not alone in adhering to tradition. All winning teams I know are steeped in the pride of their respective traditions, which become ingrained in their culture and passed down from generation to generation.
Rivalries
Traditions give rise to rivalries, especially in sports, and particularly in football. Take the recent 104th Ohio State vs. Michigan football game, and the upcoming 108th Army vs. Navy game. Both rivalries are long and bitter, with the entire season's success hinging on this one game. Far more than mere football rivalries, the Ohio State-Michigan game is a "war" between both entire states. The Army-Navy game becomes all out "war" between the two proud military branches. The "big games" define not only the whole season, but also the entire year.
The interesting thing about these fierce rivalries is the result is a two-sided coin, with "heads" as hatred and "tails" as respect. Take what many view as the most bitter, intense, personal sports rivalry of all time: between legendary football coaches Woody Hayes for Ohio State and Bo Schembechler for Michigan. Their on-field hatred was so great the rivalry became known as the "Ten-Year War."
However, a curious, ironic thing happened once both retired; they became best friends the rest of their lives. How could something so unthinkable happen? The answer is the mutual respect worthy opponents, no matter how bitter, have for each other deep down inside.