Don’t assume not. Among the reasons:
1. We may be discovering that e-books are well suited to some types of books (like genre fiction) but not well suited to other types (like nonfiction and literary fiction) and are well suited to certain reading situations (plane trips) but less well suited to others (lying on the couch at home). The e-book may turn out to be more a complement to the printed book, as audiobooks have long been, rather than an outright substitute.
This is certainly one thing I’ve noticed. If you’re just reading a page-turner, that’s find. But e-books are much more like scrolls, which everyone understands inherently inferior to printed, bound books. Even our language describes “scrolling” through electronic text. We’re going to seriously need to re-create the random access quality of books before e-books replace them.