How can someone even try to claim that Japan isn't becoming less relevant for Sony? Look at it this way,
There's 1 PS4 sold for every 23.5 people in Japan.
There's 1 PS4 sold for every 18 people in France.
There's 1 PS4 sold for every 17.6 people in Germany.
There's 1 PS4 sold for every 16.2 people in the U.S.
There's 1 PS4 sold for every 15.3 people in the UK.
Look at the UK and France. Combined they have a population that's less than 4.5% higher than Japans, and yet Sony has sold 48% more consoles in those two countries.
On top of that, most European countries consume the same types of games. so If you make a game that caters to that market, you have a huge pool of consumers to draw from even if that game has limited appeal outside of the region.
Haha well...that's one way to look at it.
"The Xbox One has way more room to grow in Japan than the Switch does!"
Good one. :)