I am no longer sure that I can parse your argument.
Are you saying that the Vita will somehow yield more sales for third party titles than 3DS, and will therefore go on to become the lead platform for all handheld games, and the 3DS will be lucky to be left with ports? Is this what you're saying?
If so then for starters I'd like to see you justify that first premise with something more than wishful thinking.
i think it will be the same situation like the Wii but maybe less severe.traditionaly the titles that did well on Nintendo platform like dragon quest will still be released exclusively maybe on it but as exclusivety doesnt make sense from 3rd party POV anymore multi is the way to go for them unless there is a lack of business sense to release on a platform that wont sell that many copies of your game.
lets say for example that there are two version of the same game.people will always choose the superior version (FPS,graphics,...).and thats what gives the advantage to the Vita.see the latest Ace Combat game on the 3DS for example do you think that they will release another version on the 3DS with such a low sales.