I highly doubt that eBooks will replace paperbacks/hardcovers. Some people don't like reading books on the internet, much less eBooks. I prefer reading regular books because A) they're cheaper than an eBook, B) some eBooks don't display images real well, and C) I like to read and collect REGULAR books.
Besides, eBooks are breakable anyway and if you break one, you'll have to buy another one AND THEN buy the books that you downloaded again, which will cost a lot of money.
Audrey Niffenegger (The Time Traveler's Wife) stated:
"I am not opposed to the existence of e-books; I know lots of people are wildly enthusiastic about them. But I have spent my life working with books as an art form and I am devoted to physical books. E-books in their current incarnations are still imperfect and they threaten the arts of book design and typography. As a book conservator I am also nervous about the digitization of books: will they be readable one hundred years from now? Or will thousands of books simply vanish as platforms and programs change?
E-books have certain advantages (they are searchable) and disadvantages (they are not beautiful objects in themselves and don’t display images very well). I’m sure they will improve over time, though. I don’t know when or if my books will become e-books. Writing me hostile e-mail about this will not hasten my desire."
(http://audreyniffenegger.com/about)
Me being a writer, I completely agree with her.