They do buy goods from publishing houses and book companies, but the discount given by publishing houses is higher than that of book companies. As for why the online discount is so low, it is their own behavior. If you carefully observe their operation, you will find that they don't make profits on paper. Many publishing houses and physical bookstores are also worried about their behavior. In fact, the profit of books (except classic books and textbooks) is not high. The low discount on the Internet makes many good books sell very cheaply. Moreover, books are different from other commodities. If it can't be sold, it can be returned. When they return to the publishing house, they will become second books. Without their previous value, when they become obsolete, they will be disposed of (repaired or pulped).