There's no need to worry about Japan's home console market anymore, because things are looking up. Here are a bunch of Famitsu sales numbers as of December 20th, 2020.
Last gen's total: 12.68m
PS4 - 9.27m
WIU - 3.30m
XB1 - 0.11m
The PS4 isn't done yet, so the final total will be a bit higher than the above, anywhere between 12.70 and 13.00m.
This gen's total: 14.31m
Switch - 14.04m
PS5 - 0.24m
XBS - 0.03m
And this gen isn't even remotely close to its end. Way to go, Japan.
Simple question to spur some discussion: Are you still worried about Japan's home console market?