Dash Kappei
Not actually that important
The big difference is the 3DS didn't have a strong direct competitor when it came to market. It's not unexpected that vita would sell less in its opening week than the 3DS which had a worse launch lineup but no portable outside of phones/itouches to compete with.
On a somewhat related note, I wish people would quit it with the whole "deserves to sell better than the 3DS" nonsense. 3DS is a good handheld with good games. It'll also almost always outsell the Vita for as long as both are on store shelves. Get over it.
The 3DS had as much competions as you can get.
It had the DS. And DS + PSP in Japan.
That is so true that Nintendo slashed the price of the 3DS while maintining the same prices for DSi/XL to render, especially the former, irrelevant.