I can't fathom how any serious gamer would consider a smartphone, even the most powerful out there, to be even remotely the same experience gaming as either the PSV or the 3DS. Sure you can play games on the smartphone, but you would almost never play any game that involves doing more than flicking birds across the screen or playing games like scrabble.
A gamer does not play smartphone games when they can play on a dedicated handheld. Other people who aren't anything more than casual gamers who are trying to eat up time in between doing stuff in the real world do not really matter.
That said, the iphone other smart phones will significantly outpace 3DS and PSV sales. And games that appeal specifically to that crowd will have the potential to make lots and lots of money. They will still never really have the depth that actual gamers require, thus will not replace dedicated systems in the near and significant future.
The day when we get modular handheld devices where we can morph a primary computation unit into a phone or a gaming device will be the day both smartphones and dedicated gaming devices die, and probably not a day before.