Because people who usually resell old games to fund new game purchases will have less disposable income available.
If console makers / publishers take a cut out of used game sales, then that is the exact amount that will not go into buying new games.
Logic, isn't it awesome?
PS.
Percentage totally made up, like that other publication that used it.
"Well certainly with the Xbox 360, we had some challenges at the launch. Once we identified that we took control of it. We wanted to do it right by our customers. Our customers are very important to us." -Larry "Major Nelson" Hryb (10/2013). Note: RRoD was fixed with the Jasper-revision 3 years after the launch of 360
"People don't pay attention to a lot of the details."-Yusuf Mehdi explaining why Xbone DRM scheme would succeed
"Fortunately we have a product for people who aren't able to get some form of connectivity; it's called Xbox 360,”-Don Mattrick
"The region locking of the 3DS wasn't done for profits on games"-MDMAlliance
