Of course, selling used textbooks can hurt authors and publishers. It places a burden on both parties to create new material and forces each to reexamine their contributions much more often than is convenient. But is this necessarily bad? Of course, it will take more effort to make the same amount of money, but I would like to argue that it is more harmful, from the perspective of society, to view any industry from the sole perspective of the producer.
One of the most interesting and important issues regarding the capitalist system of late involves the rights of the firm beyond the point of sale. The entertainment industries, for example, has hemmed and hawed at the new pseudo-industry rising around internet, and its facilitation of person-to-person trade. Falling profits after a decades-long period of prosperity have angered music, television and movie executives to varying degrees, and solicited a number of responses.
The music industry first drove up prices, hoping to capture affluent markets who would not be caught dead trading in stolen goods. When this failed, they slashed prices, but profits continue to fall. Why? Because the industry still, more or less, refuses to alter a business model that served it so well in the physical retail era.
Television and film have been slightly more successful in adaptation. First of all, they reexamined their product in its new environment, and separated into two basic categories. The first cuts production cost in order to increase margins (e.g., reality television), while the second focuses on creating a quality program that viewers will truly enjoy (e.g., Lost, Heroes, etc.).
In the first case, costs are so low that any viewership, and thus any advertising money, will eventually pay dividends. In the second, viewers will go out of their way to either watch the show live, or go to the broadcaster's website and watch there. By providing, free to the consumer, that which was once stolen, the networks eliminate the illegal industry's competitive advantage.
So: how does this apply to the textbook industry? The emerging norm of second-hand buying, now being fueled by such giants as Amazon and eBay, will inevitably cause decreased margins. Opportunities for economies of scale will go out the window, as the shelf-life of every textbook drops with every development in the resale industry. Publishers and authors will be harmed, there is no way around this, but if they learn to adapt, losses can be reduced to a minimum.
First of all, publishers and authors must work together to keep content either inexpensive, relevant or both. The first, I'll call it the "reality television approach," compels the publishers especially to cut costs in any way possible. This may be in the quality of binding, the number of pages or, simply, a thorough slashing of non-essential information. While this may not be ideal (consumers are left with less "product") it is far from unethical: you get what you pay for.
Consumers who opt for the less expensive textbook know that they are not receiving the highest quality, and are OK with that. People will watch MTV's The Real World, in full awareness that they are not receiving the highest quality that television has to offer; they will watch because it provides the fundamental, relaxing experience that television must provide.
The second, the "Lost approach," relies on high quality in order to attract a market. For publishers and authors, this means creating something people want, and marketing it from every possible angle. The first step, arguably the hardest and, therefore, most "harmful" to producers is to create a valuable product. Rather than a textbook the merely outlines a subject, publishers must find authors who are willing to infuse their own experience and insight in order to create something that is decidedly unique.
Next, multimedia content, such as a CD-ROMs or websites that give the end-consumer more resources to work with also increase value. Coupled with a simple, secure log-in system, publishers can effectively limit access to the first user only and trim away the products resale value.
Finally, authors must work to update their material as often as is necessary. Publishers must find a way to make this available to consumers, either through their multimedia programs, or new editions. New editions, though seen by a few as unethical and unnecessary money-making schemes, create incentive to by new if, and only if, the new material is valuable. If the second edition contains no substantial improvement over the first, it will not become a source of valuable source of revenue.
The ease and ubiquity of resale necessarily means that producers must work harder to compete in an environment that is becoming more consumer-oriented every day. Publishers can no longer milk their cash cows, and authors will be forced to devote more time to their work than ever before. But, because regulation will become harder every day, and would necessarily violate some of the freedoms that consumers feel entitled to, it will not happen. Industries must learn to take a punch, or end up on the floor for good.