Of course, digital copies could truly put a dent in that reasoning. However, even then there should not be a cut of revenue to the publisher if the original user discontinues use of the product (so that it's not piracy). It's like someone re-selling artwork. Presumably it's in like-new condition if it was taken care of (on in some cases, would appreciate in value even if its condition deteriorates) -- but you wouldn't hear anyone talk of paying the original artist a cut of its resale value, now would you? From what I hear, book publishers are also gearing up for a fight in this arena. They have already been breathing down the neck of used-book stores, and now e-books are adding a new twist to the debate.
There is no likelihood man can ever tap the power of the atom. -- Robert Millikan, Nobel Prize in Physics, 1923