No DLC for Halo 3: ODST?

Bungie's Curtis Creamer took some time out during the VGA's and answered the questions on many gamers minds, Was there a decision made to have no DLC for Halo 3: ODST? Here is what he had to say, "Well, that was something that we didn't really think we could do for ODST because traditionally all of our DLC has been about competitive multiplayer. That's something that we had the systems in place for. But, since Firefight is more based on the co-operative campaign mode, that was a technology that we hadn't built up to a point where we could add DLC to the game. It would have been too much of an investment to make that happen." It's a shame because Firefight was really fun, but after playing the maps a couple times at a few hours each session, you really want a change of scenery and it doesn't look like that will ever happen.