I'm not sure why we can't have a used-game scenario that's similar to how many games operate today:
Buy a used game, but pay an additional fee to play online. This happens with many EA games.
But the new scenario could be:
Buy a used game, but pay an additional fee to play period.
This way, the used-game market isn't killed, but the publisher/developer still get a cut from that used game. It would also potentially drive down used game sales, knowing that an additional fee would be required to play. So Gamestop might make a little less money, but that's better than just killing the entire used-game industry, no?