First the disclaimer: I consider Jon Krakauer a friend.
My first reading of Into the Wild gave me the same impression as many: a modern product of pampered society, who thinks he can go into full survival mode, without paying the dues, with predicable results.
It talking with Jon about it, though, that was clearly not his take. Not to speak for him, but, he seemed to think that it represented the same process that most people make at some point in their adolescent-->adult journey, although this one had defined exterior parameters that everyone could see. In this case it might be a bull moose, in another a "bull" trainman, or a corner enforcer. Jon really intended this to be ONE EXAMPLE of the journey that most face to a life as an independent adult.