Earlier quoted context omitted.
AFAICT, publishers don't donate books to public libraries. Those public libraries use our taxes to buy books. So if books are expensive then our taxes buy fewer books. San Francisco public libraries spend $200m per year, of which 15% is spent on 'collections', including books, ebooks, magazines etc. That's $35 per resident. The denominator includes newborns, infants and others that can't read or don't like to read.
Libraries also do a lot more than just provide books. $35 per resident per year for everything that libraries do provide is forking cheap, and we would be greatly impoverished if they were to disappear.
The total is $235 per resident per year.
But my point above wasn't about whether that number is high or low. It's that the price of books is paid by us, even it's funneled through taxes and librarians.