Grampa Simpson
Banned
I don't think attaching a game to an account negates second hand sales. It makes it a little more convoluted, but certainly doable. For DD games, MS could implement a system where you could "trade" games directly through their online service towards another game. For retail games, Gamestop could have a system set up to remove activations of the game once they get a trade in. Making it available for sale again.
EDIT: Another aspect of the DD service that could be implemented is that publishers could either allow their game to be purchased via traded funds or not. This gives them some options, but it would also test what liquidity does to game sales. Would games with this not allowed have lower sales on average than games with it allowed?
Why would EA or Activision actively want you to be able to trade games with people? If they want to play it they can have the pleasure of owning their own copies without having to impinge on your ability to play that game again later.
In all seriousness, I tend to purchase games with the intent of playing them eventually. I still have PS1 games that I haven't gotten around to. I expect that in 30 years, I'll still be able to play my PS1 games, and my PS2 games, and my N64, Gamecube, Wii, and Wii U games, but the PS3, XBOX, and XBOX 360 games, I'm going to have to keep living systems around to play them on. I'm pretty sure that not even that will save me for the PS4 and Durango, let alone many PC games - well, at least the PC games get cracked eventually, for when the servers handing out the DRM go down forever.