So is the Vita dead?

[Tellis]

no big RPG exists on it

Persona 4 Golden is a lot of people's "reason to buy a Vita", because, despite it being a remake of a PS2 game, it changes enough for it to basically be considered its own game. Not sure if that counts as what you mean as a "big RPG" though.

It's kind of upsetting because it and Soul Sacrifice look like awesome games but nothing else about the Vita is interesting enough to make it worth it to me.