The entities complaining that used game sales are costing them money need to do the same thing as all whiners - face the reality, and do something that actually has a shot of working.
Enough with this trying to cherry-pick the characteristics of physical and non-physical products that suit your current business model the best.
In the case of used game sales, they simply need to get in on the action. Forget resale of discs; that's a lost cause. In the near future, even where those items still exist, they'll be linked to an account anyway.
They need to get in on resale of digital purchases. Say I'm done with a game I bought on Steam. I put my "copy" of the game up for sale, for some percentage of the current "new" price. Some other user decides to buy it, and pays that price. I get a substantial chunk of it in credit - at least half. The rest gets split between the publisher and Steam. The publisher and the developer can then work out what they do with that bit.
Mind you, eventually I'd like to see an end to paying for individual games at all. Instead, I pay a monthly subscription, and play whatever games I want. In turn, the developers for those games get a percentage of my subscription fee, based on how much I (and other subscribers) play their game.