First of all, many ancient books were indeed copied, but with the passage of time, many ancient books were damaged, and the surviving ancient books rarely became orphans. Because some ancient books had high reading value in that year, they once became bestsellers and were copied by many people. Just because the service life of ancient bamboo slips and paper is not too long, some people neglect to preserve the knowledge in ancient books after learning them, and eventually they are damaged for various reasons. Perhaps only a few ancient books have been carefully protected by future generations and become orphans.
Secondly, the audience of some high-tech ancient books is very limited, and it was not allowed to copy more at that time, so the last ones that can be handed down became orphans. In fact, compared with books with a wide audience, some special industries have very few audiences and very limited circulation, so they naturally become orphans. For example, doctors, craftsmen, martial arts and other industries in ancient times paid attention to transmitting information from the inside out and from men to women, and many of them were secretly taught between teachers and apprentices. In order to prevent peers from prying into their secrets, how can we make more copies?
Finally, in order to maintain the rule of imperial power, officials suppressed other thoughts and behaviors in ancient times, which also caused many orphans. In ancient times, many kings suppressed other thoughts in order to maintain orthodox thoughts, such as burning books to bury Confucianism, destroying Buddhism and other historical events. Ancient books with large circulation and wide audience may suddenly become insecure because of this official behavior, and many ancient books will be damaged as a result. Fortunately, those who have survived have become orphans.