I should have clarified I was referring to the MH audience, which (without a doubt) has mostly moved on to 3DS, given sales of MH4. Sorry for the confusion.
Obviously there's an audience for the game on Vita, I wasn't trying to imply there wasn't or to diminish the great sales of the Vita version. I was just wondering why they didn't try to go for the potentially much bigger market. Easier to develop for Vita? Afraid of splitting the user base? It's an honest question.
To be fair, the Vita version sold a lot better. They must have been satisfied with those sales.