However, the problem with "piracy doesn't hurt sales" is that it is only true when you provide a service just as good as the pirates.
If buying your book on amazon is a hassle, moreso than downloading a PDF on a forum, then people will pirate it. Amazon requires you to search the book, put it in your basket, go to checkout, pay, then download it on your kindle and read. The forum download requires you to download it and put it on your kindle. Maybe it is time for a Netflix for Books, especially with more digital books being sold.
That my assertion holds water is I think proven by piracy being on the rise again, now that streaming services have more exclusives, making it harder and more expensive to get the shows legitimately.