More and more authors of nonfiction today make money from a number of channels other than actual book sales. The book only serves as a promotional tool for their personal brand, and is only a collection of previously published blog posts or magazine pieces. This already started due to changing consumer behaviors and declining interest in books, so by the time piracy has come on the scene, the shift had already largely occurred.
Cory Doctorow's works that were released under more permissive licensing still reserved some rights for the author. I believe he used some flavor of a Creative Commons non-commercial license, if memory serves. Point being that the method of licensing his works was still fundamentally based on copyright.
(I think the US copyright system is hugely broken and the social contract needs to be re-negotiated, but I comment here in the interests of facts, not in support of the broken system.)
If there were no copyrights, no author would make any money.