KingPK said:
I honestly don't know this, so I'll ask: can you give games to your friends over Steam without them having to pay? From what I understand, when you buy a physical disc PC game you have to put a one-time Steam key in to play it and the disc can't be used in another machine after that. I'm not a PC gamer so I might be wrong, but isn't that pretty similar to what we're talking about? Is there even a used market for PC games?
Steam games are permanently tied to your account. You can technically give a friend your account credentials and let them log in, download, and play... but that's risky, and I'm sure it's against the Steam TOS.
Physical copies of PC games these days will often come with a single-use code and an install disc (and sometimes not even the disc, I understand). It'll depend on what the publisher decides to use for DRM, but many will use Steamworks. Most, if not all recent EA titles will use Origin. Blizzard games since
World of WarCraft use Battle.net. (Previous games used the original Battle.net, but just for multiplayer and updates.) Many games under the Games for Windows Live banner will use their DRM; some older ones may just be there for the sake of branding. And many recent Ubisoft will use Uplay. In all of those cases, you install the appropriate client software, create an account, activate the code, and it's permanently yours. Basically, you check the back of the case, read the fine print, and if you find "INTERNET CONNECTION REQUIRED", then you're getting hosed somehow.
Some games may still use a simple disc check, or a CD key, or maybe even nothing at all. But they're probably few and far between—especially among major publishers. The only one that comes to mind off-hand would be
The Witcher 2. Even there, it seems like the developer may have had to fight for it with their publishers. The developer being CD Projekt Red, who are also known for running GOG.com—another online PC game store, with a DRM-free philosophy.