I'd love to write a longer commentary, but this appears to be background material for a piece on an author (James W. Hall, author of Hit Lit: Cracking the Code of the Twentieth Century's Biggest Bestsellers, which is, itself, as of the time of this writing, at exactly #1000 in book sales on Amazon).
Couple of reasons listed for books being bestsellers:
- dealing with social issues (race, sex, etc.)
- dealing with institutions and suspicion of institutions
- outsiders as protagonists
I cringe at the idea of formulaic fiction. It does seem to be successful (Terry Brooks and L.E. Modesitt, Jr., in the fantasy genre, have both written the same book over and over again and both are "New York Times bestselling authors.") And people often make the argument that there's nothing in fantasy that's original (I'm wishy-washy on that one, probably because I don't want it to be true). Of course, when someone does write something original, half the Amazon reviewers complain that it's too weird. Argh, I give up.