Stronger 3DS launch software would also have benefitted the system, Iwata went on to say.

“… If we had have launched the Nintendo 3DS after we had prepared more software by which the users felt ‘I want the Nintendo 3DS right away!,’ the transition of the sales of the Nintendo 3DS would have been better. You pointed out that our preparation was lacking in that regard, and we ourselves understand that is a point we have to reflect on.”"
This right here. Just like Sony with the PS3, if Nintendo didn't just assume everyone would purchase the 3DS just because it was the new Nintendo handheld and actually developed some more games for it at launch, the system wouldn't be doing as bad as it has been.

Nintendo only has themselves to blame. People probably got tired of there being few games on the Wii. With the DS it's been third party developers supporting it almost the entire time. With hardly any really good third party games on the 3DS at this time, it would have really helped if Nintendo would have had some more of their own games, and ones better than what they've launched with, to give reason for people to own a 3DS.

That way that would remove a persons assumption of "here comes another Wii(system with no games.")