Have to disagree with you, Small. I strongly believe that had Monster Hunter 4 been a vita exclusive, the situation for vita would be completely different. What some people seem to forget is the so-called "snowball effect".
It goes like this (all hypothetical of course):
MH4 announced as a exclusive for psvita. Hype from people. People see it as a good investment. Better initial sales. Big developers see a future in the platform. Namco announces and releases games for it (they made two Naruto games for 3ds and released a tales game for it; they could have at least made one Naruto exclusive game). Square Enix makes games for it (they did for 3ds). No droughts. MH releases and sales explode. Psvita is considered a good alternative.
What we have at the moment:
1. Before even the launch of psvita. MH4 exclusive on 3ds. Psvita has no big exclusives coming. Ninty has all the big exclusives (Dragon quest, pokemon, mario AND MH4). Why take a risk and develop for a handheld which cannot compete with 3ds?
2. No support. Some ports that do ok. More ports. Some niche games do ok. More niche games.
And that's all we have. The psvita lost any chance at competing when they lost MH handheld exclusivity. It make developers not want to take a risk with it. One game of that calibre could have made a huge difference.
Just my two cents.
