Whats weird about the DS is that my 2 nephews both of which (10, 11 years old) are DIE HARD DS fans. They spend every dime they obtain on DS games (bday, allowance etc..) ... neither of them even wants the 3DS. When I got back from E3 I told them I was playing with the 3DS and Wii U (they like Nintendo) and I asked if they were curious about either.
Both shrugged and said something like, "3DS doesn't look any better than the DS. Did you see the new PSP there?" They mainly play sprite based games, pokemon etc.. and I was quite shocked they cared about graphics. I pushed a little harder to get some more details and the bottom line was they thought the 3DS wasn't really an upgrade at all.
Then they told me, "Uncle Noid, its also $250. We're not rich enough to get that."
Personally I feel the $250 price point for Nintendo is killing them, while a $250 price point for Sony and Vita is going to guarantee very good launch numbers. The tech packed into Vita is astonishing for that value. I spent a good 20 minutes on a Vita at E3 and it is leagues ahead of 3DS in everything I saw... so in this case, I feel the hat got passed to Sony.
Of course the GAF curse will set in, we love it so its going to fail miserably lol.
edit. I do not think any 1 game is going to save the 3DS. I think the only thing the 3DS has going for it is 'time'. In a year or a year and half from now if the library has several good games and the price is under $199.. then Nintendo will see sales pick up. Anyone saying that Mario Kart or Zelda or Shamalamdingdong game is going ot spike sales is really moving 'dem goal posts.