It has always been a racket. When I was in graduate school in the early 1980s professors would more often than not either make you buy the text book they wrote and had published, or they would send you to the local Kinkos (copy store) to purchase a stack of xeroxed pages they had written and typed up. Either way, the professors were supplementing their small salaries by making you purchase their books. Now that all students are expected to own a computer and/or tablet, they could just create PDF text books and make you buy them directly from them skipping any middle parties. In undergraduate school it was a bit different. Typically we had to buy the books written by the department chair are lead professor for the subject matter. At least those were usually real printed/published books and not xerox copies.