I think he is implying (correctly) that in the absense of a robust secondary market for cars, the prices for new cars would drop -- there would be less demand f

I think he is implying (correctly) that in the absense of a robust secondary market for cars, the prices for new cars would drop -- there would be less demand for new cars people knew they couldn't resell. It's a bad analogy, though, especially for an economics professor. By suppressing the secondary market for his book, he secures his monopoly on a mandated good, ensuring the higher price.