Understandable points... I think it's really more about Sony's current financial situation and how they can't really afford to lose money for much longer (from what I gather). I think they can lose the customers who only buy used games because they don't make money from them anyway, although there would be obvious repercussions greater than this.
@Haruka - I agree that retail games are much better, and I much prefer to have a physical copy with box art etc. and I only really buy downloads for Steam/Arcade titles, but it's just a matter of time before the industry switches to a wholly digital model, which would suck at current bandwidth levels.
@El Dango - While from the consumer's point of view, you're argument makes complete sense, from Sony's point of view they actually lose money on people who buy their console at a loss, and then purchase games in a way where they don't get paid. Movie makers don't also sell you a thousand-dollar playback device for only 500 dollars. Also, do you not agree that the developers should get paid for every copy that people purchase of their game? In some bad cases they may not even be able to make games anymore.
I honestly don't see this system coming into effect, at least not at the beginning of the PS4's life, but if it does, I still see their logic behind it.
TBH though, Sony are kinda idiots. They've practically ruined the Vita in a year, and it's going to be extremely hard for it to recover, and the PS3/PSN has been pissing me off more and more as of late, so much so that I've actually switched console preference back to the 360 which I never thought would happen, so I'm really more excited about Microsoft's next console at the moment (something I never would have said a year ago)
I'd like to point out that I'm playing devil's advocate here, I'm a consumer, and as such I don't want to see this come into effect, but I still have to argue how much it makes sense.