Let's see...
Lack of JRPGs and other types of games that a lot of Japanese players enjoy.
High price
That's pretty much it. Xbox 360 didn't do better percentage-wise in the market than the Xbox did. But the 360 had a way higher amount sold worldwide than the original Xbox, and was able to sell over a million in Japan.
The Xbox One really never had a chance in Japan. The Xbox Series X will be lucky to sell 0.5 million lifetime units in Japan.
Lifetime Sales Predictions
Switch: 156 million (was 73, then 96, then 113 million, then 125 million, then 144 million, then 151 million)
PS5: 115 million (was 105 million) Xbox Series S/X: 48 million (was 60 million, then 67 million, then 57 million)
PS4: 120 mil (was 100 then 130 million, then 122 million) Xbox One: 51 mil (was 50 then 55 mil)
3DS: 75.5 mil (was 73, then 77 million)
"Let go your earthly tether, enter the void, empty and become wind." - Guru Laghima
