The momentum from MHW and frequent releases was already gone a few weeks ago, the trend was clear for awhile, so it's not a surprise that shipments were adjusted to such trends, it's a bit on the short side and not optimal but it is adequate for the diminished demand for the upcoming weeks/months in Japan. Let's speculate and assume there are plans for a price drop or another revision, like for example a PS4proslim for the holiday season, I think retailers would try to avoid big overstock of current models considering the lost in momentum and obvious short term trends for PS4.
Anyway deliberate artificial shortages to increase demand is a great strategy /jk