Consoles in Japan, slowly dying? NES,SNES,PS1,PS2.WII

[scottie]

Add in portables and your rend dies. The DS has sold 29 million sellers, the PSP has sold 3. By contrast the GBA sold 5 and the GB sold 25. The DS and PSP should be able to rack up another 20 million sellers between them

So no, developers do not need to rely on non Japanese markets