If the publishers want a cut from resales, the assumption is that the product is as good as new. (This is why the used-car sale is often considered to be a flawed analogy). But what measures would they implement to guarantee the used product merits their cut of the revenue? Are they going to refurbish it? Are they going to restore the original packaging and manuals, etc? Are they going the guarantee that the disc will be free of scratches or other defects for a certain warranty period of time? If not, then indeed selling a used game (or DVD movie or music CD for that matter) is just the same as a used car or a used anything.
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.