Seth Godin thinks so:

Textbooks have very little narrative. They don’t take you from a place of ignorance to a place of insight. Instead, even the best marketing textbooks surround you with a fairly non-connected series of vocabulary words, oversimplified problems and random examples.

I agree that textbooks of this sort fall flat on their faces, and it sounds like textbook standards have slipped considerably. But I firmly stand by the idea of a textbook. To me a single volume that takes you from zero knowledge to thorough understanding is invaluable. Popular nonfiction publishers are less likely to approach subjects that way, because it can result in hard-to-market doorstop-sized behemoths.

But I also like Godin’s alternative proposal:

The solution seems simple to me. Professors should be spending their time devising pages or chapterettes or even entire chapters on topics that matter to them, then publishing them for free online. (it’s part of their job, remember?) When you have a class to teach, assemble 100 of the best pieces, put them in a pdf or on a kindle or a website (or even in a looseleaf notebook) and there, you’re done.