Is this the end of books as we know them?

No. But it is the beginning of a symbiotic relationship with the digital. The hard copy will not go away for three reasons:

The Bathroom- Who would want to read a digital copy of a book on the can? How would they read an electronic device in the bathtub?

The Bookshelf- What the heck would you put in them if books go the way of the dinosaurs? Bookshelf makers will not let the hard copy book go away.

Cost- Right now the readers are far too expensive. The lower end consumer simply cannot afford it.