Why? 

i expect vita sales to grow, and 3ds sales to grow as well

Seems unlikely, Nintendo 3ds line up late 2013/2014 will likely be impressive. Pokemon, zelda, metorid? probably final fantasy...

Maybe when its gets cheap enough people will pick it up to accompany the ps4. Then it could probably outsell the 3ds during another software draught.

Unfortunely doesnt seem to be the case. The Vita in japan is getting a second launch about now. Games like PSO2, Tales of hearts R and Soul sacrifice all coming in one fell swoop along side a price-cut in a market that is portable friendly.

So yeah... for that to happen the Vita would require something equally stellar for a line-up and the games mentioned appeal to japan alot more than the west (even though i really want them). The 3DS numbers will surely spike a bit when luigi's mansion, castlevania and monster hunter 3 ultimate come out later this month. Also, lets not forget the huge pokemon X/Y coming out this fall.

At this point its better to evaluate the Vita like a platform that can hold its own, instead of the rival of the 3DS. The vita will eventually hit better sales with price cuts and more software in the market. The device also has a longer lifespan, so it will be in a good place eventually. Just simply expect good games on it, instead of it beating nintendo handhelds.

And since were on the topic, im a happy Vita owner and while its an amazing portable it also has shortcoming. It especially annoys me that special effects are so dull in the system for some reason.
Anyways... heres hope for the Vita because i want more Japanese games to come over. :)

That is very unlikely. The handheld market is being eclipsed and ultimately swallowed by the smartphone/tablet market. The days of the dedicated handhelds are over.

OT: No, there's no way, 3DS numbers in that region may be bad but they're still about 350% more than the Vita right now.

I meant ever, but that might be a bit long term for a bet, haha.

haha yeah like 5/6 year long lol

I think the best that can be hoped for is the Vita to end up in a similar position to the PSP with about a third of the market world wide.

the psp was pretty succesful for sony about 75 million units world wide is pretty good

That's why it's the best they could hope for now , no way is the Vita getting near the 3Ds but if it can get near the PSP in it's life time or close it's done it's job sure beating the 3Ds would be a feather in Sony's cap even if it was one region and a nice thing to aspire to, but the real world  target Sony should be aiming at is the PSP'

For all the DS PSP comparisons over the years pointing towards DS's dominance , the PSP did damn well and if the vita can get somewhere near that it has done it's job.