The Sony "base" love to change the rhetoric, when it doesn't suit them. Or move goals, anything to put Sony in a good light.
Japan was always important, a lot of global phenomenons have started there, or came from there. The PS4 isn't an American product or an English product, it's global brand that started and is based in Japan. So OF COURSE Japan is important for the PS4, no question about it.
You've lost the argument in the first three words of your paragraph, impressive I must say.
OT : It's the second best selling country, yea, but as a region it's getting smaller and smaller.