Denise Kaigler, VP of corporate affairs for NOA, has said that it's not Nintendo's intention to bring what works on DS over to Wii just "for the sake of doing it".
It only gets a console version if the company feels it would be a good fit.
"What we do is look at games that make sense to apply to Wii", she told GoNinteno at E3. "Same thing can be said of Virtual Console games. We're always looking at ways to make the experience more fun and more compelling for gamers. If we look at a DS game and see that a Wii version...experience can be enhanced, then that's what we do.
"We don't just do it for the sake of doing it. If we can make that experience more fun, more compelling, more immersive...that's what drives that decision."
Prime examples of DS games going Wii include: New Super Mario Bros., Mario Kart DS, and Animal Crossing: Wild World.
More through the link.