"provide a complete experience". However it seems that they've decided to move on from that idea or are thinking about it at the very least.
Speaking at an investor Q&A, Nintendo boss man Satoru Iwata talked about the possibility of maintaining sales after the launch of a game through DLC.
Iwata put forward the idea of providing new levels as DLC for Super Mario 3D land as a way of gaining both sales of the game, and revenue from purchases of the add on content. This would also keep people interested in the game long after they would normally get bored and trade it in.
While this was only an example and not anything like the announcement of DLC for Super Mario 3D Land, it does show that Nintendo is looking to expand it's online presence into DLC. It may have taken them quite a while, but they finally worked out that there is money to be made in selling extra content for games.
This idea does get me rather excited that we could see more content for future Nintendo games, but such content would require frequency which Nintendo is not sure to provide. Nintendo is known for taking it's time with games and extra DLC, while being very high quality, could take much longer for them to create than many other developers.