In their own ways, Jon Steward and Stephen Colbert represent two main American archetypes:  the humble man and the braggart. When I was growing up, the humble man was the ideal we all aspired to (would you be happier with "to which we all aspired"?). The shy, reticent Gary Cooper playing Sgt. York or the sheriff in High Noon was the ideal American hero. The French with their fancy clothes and braggadocio manner were one thing, but real Americans were quiet, even taciturn. Think John Wayne. Think the great Baltimore Colt quarterback Johnny Unitas.

While not taciturn, Jon Stewart is in this tradition. Often his humor is based on him being wrong, the reasonable but humble everyman.   

In my memory, the first of the braggarts was Mohammad Ali but, really, the braggart archetype is older. George Washington went to the Continental Congress hoping to be appointed Commander in Chief of the American revolutionary forces and to accomplish that end, he had a natty powder blue General's uniform made so he would look very generalish. Nothing reticent there. All the Civil War generals before Grant enjoyed their displays of splendor (when Grant first arrived at General Meade's Headquarters, he snarkingly said that this must be Caesar's Army with all the flags and pomp). Now, it is pretty much universally considered manly to put on a display: think almost any NFL football player after making a touchdown. And nobody does it better than Stephen Colbert.