Since yesterday I have started to remember more about the movie (it was a long time since) and I am starting to lean towards your interpretation. There are many clues, as you say. On my watchings I always took it to be one of those movies where they don't feel the need to show "Book 2" because "Book 1" was the interesting part. This movie is great. I always thought it was good, but now I think it's Great Art. This movie scares me shitless now.