it was under 3k on vita because tracking ended at 2,900 and the game didn't chart. it could have done anywhere between 0 an 2,900. on ps4, it sold 8,700.
the way japan retail works is that they'll buy stock and that'll be that. there's no such thing as a publisher-covered markdown like there is in the us or europe, so 8,700 on ps4 is probably more realistically like 12,000-14,000 overall, eventually. and ps vita would be around 3,000-5,000. add in 10% for digital sales (another 1,000 units) and this game will probably do around 15,000-20,000 overall. it's a massive bomb, a failure of leadership, and probably the end to this franchise, but considering it can still come to ps5 and switch in japan, where it could get another 10k in sales there means that a western version based off those platform releases would be pretty likely.