My local library had books 1-3 and 5-6 of a series I was reading by an author who I own all of her later books. I even tried to find a copy at the local used shop, thinking I would read it and then donate it, but due to her rising star they had printed new editions in a completely different style, and size. I ended up pirating a copy of that book instead. Then bought the audio book for a book I already owned as penance.

I suspect when there are gaps that either the counterfeiters win or nobody wins.