The interview is worth listening to, but I'm more interested in what wasn't discussed. Mr. Conley clearly sees things from the industry viewpoint, and it sounds to me like Joe Wikert does as well. But I see things from the student viewpoint, and I noticed an important detail that they glossed over.
You see, I know the real reason publishers like custom textbooks.
Professors like the option of customizing their textbook, but publishers like the idea because custom textbooks are profitable. They're a lot more work than doing a large print run of a single title, and they sell for less, but they're still profitable. Did you ever wonder why?
It's because there's no (or little) resale market. So every student who uses a given custom textbook is going to have to buy it from the publisher.
If a professor pulls together material from several sources into a custom textbook, the students who use it won't be able to resell it (except to the next class). It's likely that no one else will be using those same chapters at another school, so that means that the students cannot go online and sell the textbook. The student is stuck with the full cost of the textbook, so whatever great deal that you think they got on the price of the textbook isn't one.
On the other hand, if a professor uses a stock textbook then the students can sell the textbook on any number of websites. They can also buy them there (oh, the horror!). And that is exactly what publishers want to avoid.
Folks, I have an old rule of thumb for situations like this. When someone is excited about selling you a cheaper product than what you usually buy, don't spend your money until after you figure out what is in it for him. In this case, it's the lack of a resale market. Publishers love it, but at the same time it harms students.
Used textbooks (especially ones on the internet) are the bane of publishers everywhere. Back in the old days, students had to buy locally. That limited competition (and kept prices up). But now, thanks to the internet, I can buy from anywhere in the US. The internet has created a single textbook market and it's forcing all sellers to compete, and that drives prices down.
The used textbook market is also why publishers put out new editions every few years, but that's a topic for another post.