This idea expressed by McCandless early on in Krakauer's account gives us a key insight into his personality and worldview. His is not an original idea, in fact we saw many people come to the same conclusion during the late 1950s and 60s, when young people began to explore alternative styles of living, even to the point of establishing communes because they had become disillusioned with what society and their parents expected of them.
McCandless is cut from the same cloth, and has the added motivation of his parents perceived betrayal. Chris is very much his own man, and a key event in his final evolution as a person is his renunciation of worldly things, including the promising career and privileged life that probably awaited him. Adventure and a new life beckons to most of us at one point or another, but few of us take the definitive steps McCandless did, and I think that is a key attraction for us to his story.