When you read a paper book, you can be certain that the content in it is the same as when it was printed, and hasn't been edited or censored since you bought it. It can't be taken away from you by the publisher, except by physical force. You can resell it at will. Publishers and retailers who wants to try different pricing strategies can do so without facing the powerful control of Apple or Amazon.
I plan to keep on reading ebooks, but I'll buy the books I actually care about in physical form.