N64? The only Japan appealing game for that system is paper Mario really. The planned FE: PoR and mother 3 WOULD have helped. A lot. But both were pushed. The Saturn was actually the main competitor to the ps1 in Japan. Saturn sold well there with it's much better 2d graphics engine than anything else.
By the time the ps2/GC/DC rolled around... The GBA was absolutely kicking ALL KINDS of ass with its RPG lineup. Ps2 still sold VERY well for the same genre but every other home console was almost irrelevent via GBA.
Then the psp/day rolled round and literally EVERYONE made RPGs for either of them, or both (looks at KH and disgaea 1). Plus by this point console games became way to expensive to make for B tier devs.
Seriously though... WWHD as a system seller example in Japan??!! Zelda was NEVER a system seller after LTTP in Japan untill BotW rolled around and gave Japan thier open world fix.
