It's more than just rentals. Buying from Gamefly is basically buying brand new when it comes to the PS3, at a much cheaper price, even has online passes unused.
It's about getting some money back when you buy a game.
If a publisher institutes DRM, they're going to hang themselves. People won't buy until the price goes down. So if they were losing to Gamestop before, they're going to lose to lower prices later.
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