It's an incredibly pretentious thing (for the interviewee) to say. Why not just concentrate on a good story, well told? It's up to history to judge whether something is great, let alone the "Great American Novel".

There have been plenty of "great" American novels, by the way: The Catcher in the Rye, To Kill a Mockingbird, Moby Dick, The Adventures of Tom Sawyer, The Great Gatsby, The Old Man and the Sea, The Grapes of Wrath, In Cold Blood... I could go on. Or I could say something a little bit snooty, like the Great American Novel turned out to be a film (I don't believe that, by the way, but I've heard it said).