What's happened to you, Nintendo? it's like I don't even know you any more.
With 3DS vs. Vita, I think both consoles are now appropriately priced. I think the biggest problem for 3DS is that it's very difficult for consumers to tell what the REAL difference is between it and the regular DS, making its original price point seem completely ludicrous to anybody on the fence. Nintendo's non-existent marketing hasn't helped with that, either. The fact that none of its games have even caused a ripple in the mainstream media is another huge factor. I think Nintendo's fear is that 3DS left a bad first impression, and that a whole group of people has already dismissed it.
I think Vita's pricing, while more expensive, is easier for Sony to justify in a way that customers understand. It's pretty obvious that it has some powerful hardware under the hood, and its price is close enough to a $200 iPhone for people to understand what they're paying for (I also think the market these days is more open to pricey mobile hardware). Besides, I don't think they're really going after the same audience anyways. Nintendo loyalists would probably never buy a Vita, and Sony loyalists would probably never buy a 3DS. Most of the rest of the casuals are probably just playing Angry Birds on their iPhone 4, and couldn't give a crap either way. That the big difference with 2004 vs. 2011.