User blog comment:Spawny0908/Rockstar Announces Fan Appreciation Red Dead DLC (and it's FREE!!!)/@comment-2113545-20110718124855/@comment-3455248-20110718175801

Probably not - software updates need to be locked down well in advance of release. Even a relatively simple thing like adding a new multiplayer character has lots of "overhead" for integrating into the game and testing. A whole DLC, even a small one, has that overhead for all of its individual parts as well as the entire release as a whole.

Even though the DLC will be free for us, Rockstar has to pay Sony and Microsoft a lot of money to get it in their stores and any time they release a patch, so it's something they need to get right the first time (which again means lots of testing). I think it's most likely they either underestimated that timeline or else they ran into some last minute issues that prolonged it.

Sorry to be a downer, but I"m a software guy so I'm all too familiar with the answers behind the "why is it taking so long" question.