I’m saying that unless the university buys all new books and gives them to students, that it is impossible not to have a used book market. If a bookstore did not sell used, then students would start co-ops(and properly manage them), greek organizations would get serious about their text libraries, and of course you have the internet.

Therefore, to say that used books drive up the cost of new books is merely academic and distracting to the real conversion of finding methods for lowering textbook costs.

To say that new books would cost less if more of them were sold is a matter of economics. Textbook (and most other physical goods) cost some large, fixed amount to produce the first copy, and then much lesser amounts to produce subsequent copies. A publisher’s ability to sell more subsequent copies spreads the fixed costs of the first copy over more units, lowering the per-unit costs of all copies.