Worth noting this is the week the new taxes came into effect in Japan, which is why Switch dropped so much. PS4 sales were halved too, but half is a smaller drop when you're selling 24k than when you're selling 190k.
Taxes played a role but they are being overblown.
PS4 had a promotion going on in the last few weeks which has now ended.
Switch had Lite+Zelda 2 weeks ago and DQXI+special edition OG model last week.
Big drops were going to happen regardless of the tax hike.
When the herd loses its way, the shepard must kill the bull that leads them astray.