I wonder how PC gamers feel. They have been out of the used game market for ages, yet PC gaming is still thriving. And I've never once been able to buy a used game for my Android phone or tablets...
If they block used games, they will still survive and thrive. People will still buy games. Some people might buy less, obviously.
Or as others have said, it could be more incentive to have better initial prices or sales going on. Instead of a game staying at $60 for 3 years, we may see it drop much more quickly. After all, the publishers will make much more on a new $30 purchase after 1 year than they would on a used $30 purchase after 1 year. Since used = 0 money for them...
The prices used game stores charge are an incredible rip-off to begin with. Why risk buying a used game for ~$5-10 less than full price when the game disc could be crap. Sure, most places offer guarantees and exchange policies, but that's a hassle and the time + trip to go to the stores keeps taking away from that paltry $5-10 savings. The people that only buy used games now, will simply wait for better deals to buy their games, or they will simply buy less games than they normally would. Either way, that has 0 affect on the publishers since a used game sale does not count for anything to them or the official sales figures.
The only thing I can understand is wanting to sell your games after you beat them, to get back some income to go towards new games. That is the only remaining valid argument against banning used games that I see.
Either way, no matter what happens, consoles will still be fine and people will still buy games. People claiming they will stop gaming is ridiculous. Let me know how many of your Android/iOS games/apps, PC games, etc that you guys have bought used or sold recently :)