Problem is, PS4 needs already a promotion to get above 10k now. Even a 10k Yen pricecut combined with FF7R and GoT won't keep those sales up for long anymore.
It doesnt need to sell 10k or above eveery week. It only needs to average 10k for the next 2 years. I think it will sell at least 6-7k per week then there will be boost here and there to make up the 10k average