Why aren't e-textbooks selling?

<p>I use ebooks a lot for class. Our library subscribes to various online collections and they're very handy - especially with the search functions etc. One collection even autoreferences if you copy paste quotes! I don't mind reading on a computer at all - I'm invariably typing an essay at the same time, so it doesn't make much difference. And as for curled up with a book, well that's what laptops are for! :D</p>