Dont really blame publishers for heading this way. In some ways the trade in market hurts publishers a little bit like piracy (with the exception of 1 person in each "trade in chain" actually buying the game).
Singly Player games are more likely to suffer though, games like Bioshock / Devil May Cry 4 / etc are more likely to get traded in as there is no ongoing multiplayer life in the game.
In my opinion it is just the retail companies getting greedy / too worried about the potential dominance of digital distribution in the future. There are already plenty of viable game rental services so i dont see why retailers cant hop on this bandwagon.







