Reinhardt argues that: Choosing a textbook for Economics 100 is like choosing toothpaste. There are as many textbooks to choose from in the bookstore as there are brands of toothpaste in the supermarket. Furthermore, just as the “new, new” toothpastes do not differ very much from what they replace, neither do the new editions of textbooks released every three years or so there is just enough changed to destroy the used-book market for the previous editions. Finally, there is not much more substantive difference in the structure and content of introductory economics texts than there is among different brands of toothpaste.
He adds: It appears that to be publishable, an introductory textbook in economics now must fit snugly into a cookie-cutter mold that appeals to the mass market for textbooks, which now includes high schools. This requirement dictates the remarkable homogeneity among introductory economics texts and also explains why many of them do not engage Ivy League students. In their quest to tailor their textbooks to the mass market, some publishers even highlight with yellow markers passages in the text they deem important. The thought appears to be that students either are preoccupied listening to their iPods while reading the text or are just plain too dumb to highlight important passages on their own..
As pointed out in a comment to Mankiw’s post, this last statement is possibly true is one substitutes publishable with marketable. As an example, the comment points out to the self-published Introduction to Economic Analysis textbook by McAfee, R. Preston (2005). McAfee released his book online under Creative Commons license. The book is available from here.