Now both handhelds must start doing good in the west. In the longterm, I just can't see Japan keeping the handheld industry alive for both 3ds and vita. They need the west to keep their systems a float (longterm). The sales in the west are currently horrible for both systems (3ds and vita).
Predictions for LT console sales:
PS4: 120M
XB1: 70M
WiiU: 14M
3DS: 60M
Vita: 13M