Yep, this is the reason I love this game too. Not working on an expansion until the original game is older, better, and of supurb quality (more so than it already is) is a great way to show the customers they care about them more than making sales on some boxes.

Just look at Age of Conan (yes, I've got to comment on them), they've got an expansion already planned for next year, moved a portion of their original developement team to working that expansion, and yet they still don't have some of the game's main features in yet; and it's 6 months after launch.
http://www.massively.com/2008/08/22/age-of-conan-expansion-concept-art-unveiled/

Seeing games work on box-based expansions before they're even old enough or stable enough to stand on their own two feet with the original is just a sad, sad thing.