Whether the print run on a book is 500 or 50,000, there will generally be a couple hundred copies set aside to be divided between the creators and publishing staff, because people who work to bring the book to you deserve to have copies for themselves for their efforts.
And ultimately, it's the collector community that determines the value of our comps. ‘Printing money’, as someone put it, is never a given. No one would be casting aspersions on what is SOP for hundreds of books a year if the market decided all these were good for is lining birdcages.