I blame it on a number of things: I don't recall Vivendi Universal Games (the publisher) doing much, if any, advertising. Since they own had rights to the books, they were not allowed to use any of the stuff from the LOTR movies. Finally, The Hobbit is just not as popular overall when compared to the LOTR trilogy (whether it is better or not is up to debate, I never read any of them). It got good reviews though, so I wish it would have sold better based on that.