Wouldn't be the first time demand was underestimated on Vita. Demon Gaze/Monster Monpiece/Dragon's Crown all suffered from first week sellouts (iirc, 95%+) before being restocked.
Though, I feel there's less excuse for FFX than there is for those other 3. The first two were just niche games which got lucky in a drought and the latter was a surprise hit. There's very little surprise about Final Fantasy being popular.
I wonder how this'll affect digital sales. Again, with the other three games, they all benefited from inflated digital numbers thanks to unavailability at retail.







