Okay, when we're talking Digital Distribution; we're already talking about a pretty much pure profit center. You can sell as many as are demanded. There is virtually no extra cost per unit once the cost of production has been covered.
In this system, I imagine you would have a certain profile, and when you purchase a game digitally, it would be noted in that profile. You would have to access this profile every time you play to verify that your profile is still authorized to play. You could then "sell back" your access to that game; removing the authorization to that game from your profile. This could also work to create "digital returns".
They wouldn't go through the trouble of making you uninstall or delete it, or move the information on your hard drive to the next user's PC, they would just deactivate your account and when the next user purchases it, they just download the software from the server (they might use p2p technology in this scenario, but not necessarily a specific user X to user Y).
So, essentially, the second user is receiving exactly what a user buying new would receive. Really, it could be sold back and resold at the current retail price of new because no value would really have been lost. However, to make a profit, the retailer would want to buy it back for less than what they sold it for and resell it for more than what they bought it back for. The resell price could be the same or less than current retail price and still be profitable to the retailer; and reasonable for the purchaser as both new and used would be the same product. However, that would not create incentive for a new buyer to purchase used over new; and the retailer has more profit with used. So the retailer would create the incentive by offering the "used" versions for less. This would then necessitate the retailer being accountable to not sell more "used" copies than had been bought back.
In short, it would end up working like the current "pre-owned" market, without the risk to the customer of a broken disk or missing manual. So, Yay!
My one gripe is this royalties nonsense. Pre-owned is not piracy so long as there still remains only as many copies in use as were sold new. Also, the number available for purchase is limited by the number of originals sold; you can't sell 1000 used disks if you've only ever sold 500 new. This system would digitally enforce that. When someone circumvents this by creating copies and cracks, that is piracy. It happens with disks and with digital distribution; however, those aren't the ones getting sold back to retailers and resold.
When Ford makes an F-150, they sell it to a dealer, and that's the last direct profit from the sale; they don't get any more money if it is then sold to another owner directly, given to a friend or relative, or sold to a different dealer. They actually realize a direct cost per unit sold. Never have more F-150s been owned than were sold. The same has held true for any other physical product.
In the digital distribution arena, the same rules can be tracked and enforced. Yes, they can be circumvented, but that is an inherent risk of the medium. A risk that is better mitigated by not treating paying customers as though they are the criminals (which generally leads them to determine that they might as well be).
If we apply what "intellectual property" proponents have to say about digital distribution and royalties for resale, or no resale, to any other property; you would own as many houses as you have lived in, which would be handy because you would also have every car, computer, piece of furniture, television set, game console, pencil, pen, dish set... you get it. Everything you buy; you would either keep or throw out. There would be no assets because there would be no resale value, everything is an expense. Nobody wants this, and I think digital distribution people get that point.
Now, they want people to be able to resell, but they want a cut. So now the developer who built your house gets a cut when you sell it, and every change of hands afterward. If you give your F-150 to your kid, you have to pay Ford 5% of the current retail value. Let a friend borrow your pencil, Ticonderoga gets a penny, and a penny again when they hand it back to you.
I am aware that I am using a twisted form of reductio ad absurdum. Is the problem in that I'm using it, or that it applies?