@ Pineapple, wow I've asked people to elaborate with their posts and you certainly did that. I'm not saying that I actually think New Super Mario Bros. will outsell Mario Kart Wii, I just don't think it is as clear cut as other people posting seemed to think.
I'm not sure how your numbers show that Mario Kart Wii didn't boost Mario Kart DS. I think the fact that the 4th 52 week period being higher than all but the 1st year is because people bought Mario Kart Wii and played it, but then after playing for awhile wanted more Mario Kart which led them to pick up Mario Kart DS in the second half of year three and year four. I.e. I don't think that the the increase in sales for New Super Mario Bros. DS will be immediate after the launch of the Wii title, but instead after people have played and enjoyed NSMB Wii they will pick up the DS title as well. Also, I haven't looked up, but was NSMB DS not bundled in its third year for the first time? Which would explain why the game saw its increase in the 3rd year, and not part of some trend on the DS.
Also your assumption that the DS will have to stop selling before the Wii does, I'm wondering why you think that is. The DS continues to outsell the Wii by large amounts each week, and has done so without a recent price cut, or many high profile releases.
For not using only one week of data, that is why I also included the second column with the average weekly sales over the last month.
Finally, I think in addition to New Super Mario Bros. Wii helping NSMB DS, New Super Mario Bros. Wii might actually hurt Mario Kart Wii. Before Wii Sports Resort, Mario Kart Wii was basically the last high profile game released on the system along with Wii Fit. Now that this holiday has Wii Sports Resort, Wii Fit +, and New Super Mario Bros. Wii, I think the people who had been picking up Mario Kart Wii with the system, might pick up one of those new titles instead.
And just to emphasize, I'm not saying that I think that is what will happen, just that it is a possibility.
