Dan DeMatteo is certainly correct in his assessment of used game buybacks supporting new games sales, and if every (or any) publisher were only a publisher, with no developer component, that would definitely get more traction with them. There are a couple of psychological issues that somewhat negate the value of his argument for publishers:
The lesser is that, as I learned when putting together an aggregated subscription download model, every publisher thinks that his content is the train upon which everyone else is getting a free ride. But, they tend to be able to get over this perception and generally do what needs to be done.
The more significant issue is that developers hate used game sales because when they go into a Gamestop (and they all do) and see their new title being sold as used, with no profit to them, it drives them right up the wall. Every successful publisher has internal developers that feed this emotion into the corporate psyche. Whether internal or external, developers get their primary benefit from sales of only their specific title, and the sales increase they might see as being part of the ecosystem is too indistinct for them to value it appropriately.
If GameStop wants to change the reception of the used offering, it’s the developers they need to sway.