LOL. I agree with your story line and predictions.
(I think Harry POtter is used as an example both because it's popular and because the later books are very long and somewhat difficult due to complex plot and language. I love HP, but I also do think there are better books out there. "Difficulty" is something that's quite...difficult to gauge anyway, as one comes to see after checking enough Lexiles. A book can be challenging due to themes, use of symbols, pace, language, length, plotting, sentence structure, subtlety of ideas, references...and a short book with simple language can be difficult.)
