I read an article that says 56% of console owners do not buy games, they share them between friends and family.
-Of the 44% who do buy games, about 85% of them buy used games.
-On average gamers spend ~23% of their gaming budgets on used games.
http://www.gamespot.com/news/6343451.html
Publishers and game makers are going to use this info as a way to go all digital or keep pushing the online code sales that have started already.
Me personally, I don't buy used games. I just wait for the inevitable price drop and or/ GOTY editions where I can get most or all of the DLC and the game for $30-$40