My memory is vague by now, but wasn't John Galt more of a "question" (who is John Galt) than a character through most of the book? That's true, for much of the novel, the "who is John Galt" is the common response to the question of why the modern civiliziation has basically gone to hell. (Though Rand, the master of literary pranks, had Galt, dressed as a beared and desheveled hobo, using the phrase as well)