Could it be tied to the Marine Corps' great emphasis on history and tradition?
Let me just begin by saying that I am not a former serviceman, but I have worked with all the branches of the armed forces over the years at the battlefield as a park ranger.

My observation supports the statement above: in general the Marines I worked with were always the most knowledgeable about their history, customs and traditions, as well as military history in general. That's not to say that the other branches were not, but I have great respect for the USMC and how the Marines instill a sense of history and tradition, while other branches emphasize modern warfare and technology only. I think they can work together.

Cheers,

Todd