I think the real key here is what you mentioned about the turn-around time on the used-games business as-is. Less than a week after a game hits the shelves, you can wander into a GameStop and find used copies for, say, $40 instead of the retail $60...and what's even better, the guy who traded it back in during that week probably got only $25 for it. GameStop then goes out of their way to promote these used copies, since they turn a much larger profit on them than they would on new ones. It's an incredibly shady business model, and I don't blame publishers/developers for wanting to cut into it.
(Of course, I'm not applying this to older out-of-print titles, which are pretty much fair game as far as used copies are concerned.)
this post kind of reminds me of back when i worked at a pawn shop. and two common items happened to be dvds, cds, and video games, and other copyrighted items (like computers with windows installed). it occured to me that we were selling items that the buyer had no legal right to use because of the license restrictions (more likely the previous owner violated it by selling the item to be resold). i always wondered how such businesses get away with resale of copyright material with no returns to the copywrite holders, especially after the major crackdowns in pirating over the last decade and a half.
of course historically it has been 100% acceptable to sell and buy used media (records, tapes, vhs, books, etc), with no concern from copyright holder. cds dvds and video games are no different in many ways from the media of old, so it seems to me to be rather greedy of the copyright holders to get away with crippling the used media market now, when they did not do so in the past. spending money on one shot items seems really bad for the economy (it eliminates a niche and restricts trickle down).
IMO, DRM are killing my playing pleasure 
I have a very, very, very LARGE collection of PC & consoles games, the oldest of them don't had these ****ing protections, only a CD serial number, like HW2. I will precise that I BOUGHT these games. Videogames are my passion, and even I am not rich, I bought them.
Some games, like Ubisoft's ones, need to have an Internet connection available permanently to play, even in single player mode. This is awful. I have only a ****ty 3G connection at home, with limited capabilities, because I live in the middle of nowhere.
Why should I mess myself with another thing than the REAL price of the physical support of my game ? I know, this is the future (look at this : www.onlive.com), but I'm afraid of this future.
It's because of that I really appreciate GOG.com : no DRM, infinite DL of a game (i.e. if you lost the file), good price in regard of the fact you don't have the physical support, goodies and good support.
this brings up another thing drm, multiplayer passwords, dependence on activation and multiplayer master servers, and the like will eventually destroy, a games life span. i still have games going back to the early 90s, and many of the old ones still work with the right os or emulator, most of the ones that dont work are because of an api version incompatibility. when i buy a game i expect it to be functioning 10+ years down the line, after ive been through 4 computers a dozen email addresses, and thousands of different ip addresses. i expect that game to still work as good as when i got it, without any features being crippled. i havent seen drm cripple an old game yet, of course i dont buy very many modern games.
im concerned that some of the meathods theyve implemented to stop piracy have made the games such that they will be unplayable after the developer deems their service life to be over and withdraws support for them (including any servers they may require). i was disappointed when freelancer multiplayer was removed, fortunately some moders and/or hackers got together and remedyed the situation. some developers actually care and take steps to make the games function after they decide to stop supporting it, but most do not. as games age id like it to be the developers and not the hackers and pirates (and sometimes modders) that perserve the games for posterity.