IMO, the only way for physical books to exists alongside ebooks is by bundling the ebook with the physical book, similar to movies. It baffles me why publishers haven't already done this, but then again...publishers aren't the brightest people.
Some publishers offer the ebook + physical book combo for less than buying them separately. For example, you can get the following deal on a particular book from O'Reilly:
The fact the ebook costs more than the print book is just laughable. It reminds me of Ticketmaster's "delivery fee" that they charge when you print tickets at home.
This is the missing piece for me. I still want to own the physical book, but I would love the convenience of being able to load a bunch of books on my Kindle and take it on a trip or something.
Plus, think of the lock-in that the stores are missing out on. As a Kindle owner, if Amazon offered me bundles, I would probably never buy another book at Barnes & Noble.