Looks like the gap between AC DS and AC:3DS is only going to get bigger. And Mario Kart 7 is going to be falling below Mario Kart DS.

It never really surprised me how NSMB 2 hasn`t been doing better at retail. Visually, it expresses the same experience for the third time - and on a system that couldn`t grab the casuals like DS. Not to mention that it focused so much on gold coins that it probably have the impression that it was a focus for the game.

Of course that among other things, Wii U`s NSMB suffered from having the 3DS game so close to it`s launch.
Personally, i don`t really feel like jumping into that game after playing the Wii U game. It feels like it`s the same kind of experience. I presume gamers that bought the 3DS game instead might be feeling the same way.

Mario U will always be a good and safe purchase for those who buy a Wii U. Problem is, those are so far, not in sufficient numbers.
Just Dance 2014 is just another victim of Wii U`s lack of appeal. Not to mention that if people who are only interested in buying the game can already do it on Wii. It`s a tough sale.

Lots of things wrong with the OP...

1. Art Academy 3DS data is incomplete. For whatever reason, we don't have data from EU for that game, and EU just so happened to be the biggest region for the DS game according the data we have.

2. Brain Age only has data from the US, and even that data is sketchy. Clearly Brain Age 3DS was not as big of a hit as the older games, BUT I'm damn sure it didn't sell less than Nikoli's pencil puzzles as our data suggests.

3. Just Dance has been dropping in general. Just look at the Kinect versions of the game.

4. NSMB 2/U were available digitally. In the case of NSMB U the timing is so different from NSMBWii that a comparison is simply silly. NSMBWii launched with an install base of at least 30 million. NSMBU launched with an install base of 0.

So... the only real solid example is Nintendogs, and even that is complicated by the fact that it's a launch game.

are you referring to their sports titles cause i would argue some of them have seen a decline but its cyclic, that is the ONLY series of games that just wont go away. People like sports, they like to feel they are part of it, and their is no other way than with updated rosters and stats and such. Plus the changing technology ensures that it feels fresh at least every couple years. 

What makes Just Dance different? Its not a sport, it hasnt been around for that long compared to sports titles. It has competition (crappy competition, but comp nontheless). People just loose interest.

Meh, let them go play on their smartphones. If 99 cent games are enough to hold their attention, then they can have them.

Nintendo should focus on creating/acquiring three more diverse core IP to broaden their IP appeal. James Bond and two new IP with broad appeal that don't have cartoony mascot characters would be a good start. Nintendo already has Mario, Pokemon, DK, Kirby, etc. it doesn't need more of those, it needs franchises that appeal to a different crowd to strengthen their overall portfolio.  

There are a lot of casuals on Xbox and PlayStation so I doubt that there won't be any kind of casuals for Nintendo's platform, if they want to "enjoy" cheap games with utterly low quality comparable to those games right before video game crash from 1983 then so be it and latest news and reports indicate that developers are flocking away from smartphones since it is unprofitable for them.

If those casuals want decent games they either need to game on PC, consoles or handheld's...

It's important to remember that around 20% of New Leaf's sales are digital and won't show on the chart. The red line is actually as far above the blue line as it appears to be below it. We don't know how big it is, but MK7 also probably has at least a 10% boost in sales from digital, putting it around half a year ahead of the DS version.

Link please?

At least in the US, unemployment peaked around the same time as NSMB Wii.  Yet that is the game that is far ahead of all the others in the comparison.  Some places have certainly gotten worse, but generally things have improved since 2009, and things were significantly worse in 2009 compared to 2006.

I'm glad somebody pointed this out.