I'm not for blocking used games but I do think that people largely ignore the fact that the same 2nd hand games they're buying for $15, they can probably get new for under $25. A lot of the same forces which determine 2nd hand prices at retail determine new game prices. People always go for the 2nd hand purchase because it is that bit cheaper, not because they can't afford it new.

No used games? Who said that?

How much % wise do you think are doing this. Are people really that cheap that they would want to save 5 dollars on what would have been a 60 purchase? Maybe. I buy my games new 90%, but that comes from me selling or trading in older games, otherwise there is no way I would be able to buy. Maybe not that extreme but i wouldnt own anywhere near the amount of games i already do.

Well from my own personal experience used games at retail are often only a fraction cheaper than the new games, I shop online alot at places like Play.com so its possible physical retailers may be more dramatic in their price differences. But here is a quick comparison from recent releases, cheapest new prices vs cheapest pre-owned. I've excluded ebay and they're based off only a quick search. 

Crysis 3 new- £16.98 (Zavvi)
Crysis 3 used- £15.06 (amazon)

Tomb raider new- £17.99 (play.com) (average price around £22)
Tomb raider used- £16.94 (amazon) ( average price around £18)

Bioshock Infinite new- £29.99 (play.com) (average price £32)
Bioshock Infinite used £26.98 (play.com) (average price £28)

Dark souls new £17.98 (zavii)
Dark souls used £11.55 (amazon)

random note: xbox360 games are often cheaper than PS3 games, don't know why :/

Of course this isn't necessarily representative of retail but still, which I know I sometimes does 2 for £20 for games which cost £15 each but still I think if you can afford pre-owned, you can probably afford new. just gotta look in the right places. Where Trading in games is concerned, I haven't done so for like a decade so I don't know the value of it, how much do you make off a fairly new game? 

I absolutely agree with you, that's exactly what i think. Unfortunately this new kind of DRM is already being accepted as we can see based on Xbox One's preorder numbers and the general acceptance of PS4's DRM(if it actually has one) in gaming forums. The sad truth is that most gamers simply don't care about anything if they can just buy the newest media-hyped game.

Part of me agrees with you when it's literally a 5 dollar difference at Gamestop.  Support the developer directly.  Not sure how Gamestop gets away with it but they do (at the end of the day, guarantee that the game will play is helpful to their cause).

However, it becomes a different story when I can save 20 dollars on Craigslist.  If someone wants to play the newest God of War and then sell it to me for 45 cash only a FEW DAYS later, then that is their porragative.  Techncially, that game would cost me 60 PLUS TAX, which is 7.75% in my neck of the woods.

20 bucks is 20 bucks.  Adds up to at least 1 new game every 3 used I buy.  I buy a mix of used and new games, depending on how badly I can resist the urge to pick it up new.

Also, getting a person to KEEP their games seems like a much better way to stifle the used game market.  I never sold a COD game or Mario Kart Wii etc.  because of the multiplayer.

Gamestop or any used game dealer take a huge cut on the whole 'transfer of used game'. You sell them a game for $12 , they resell at $48. None of this money goes back to the developers.

So even under your hypothetical, the buyer saves $12 (20%). And the developer gets exactly as much as every other creator in every other field does from a second hand sale of its product ($0).

And never mind that Gamestop isn't the only way to sell a used game.

Who knows!! Too many rumors flying around. People need to wait till E3!!

Who said that? Microsoft did. http://www.eurogamer.net/articles/2013-06-07-microsoft-kills-game-ownership-and-expects-us-to-smile