Anyone who is aware of advertising knows the "New! Improved" has log ago lost its luster. Now its all about "branding". Basically, an ad identifies a particular niche of society, associates itself with that niche, then markets to those who would like to imagine themselves a part of that niche. Whether its sexy partiers in Jack Daniels ads or wholesome concerned parents serving KFC to their children, its all about the branding.
The Whitman ads are effective in this regard, in my opinion. They speak to a century-old tradition of exhuberant, rebellious, sexually adventurous, bustin'-to-break-free American youth. This is a literary tradition going back to Jack Karouac, to Henry Miller, and yes - to the extravagant Walt Whitman, too. The 'tradition' of rebellion. Levi jeans has its own century-old tradition, the last fifty year of which has also been associated with youth. So branding yourself an icon of the historical continuity of youthful exhuberance seems like a good move.