Why do Japanese gamers prefer 3DS over PS-Vita?

[cusman]

I still don't think it is a software problem as much as it is a marketing problem

Why doesn't [Smart As] sell PS-Vita hardware in Japan when [Brain Age] moved tons of DS hardware in Japan? I have [Smart As] and it is a better [Brain Age] and there is no 3DS [Brain Age] announced.

Ragnarok Odyssey sort of like a Monster Hunter game isn't it?

Isn't LittleBigPlanet Vita a good answer to Mario?

PS-Vita already has it's Super Smash Bros or closest equivalent in PS All-Stars Battle Royale while the 3DS equivalent is 1-2+ years out.

I suppose there isn't any Mario Kart equivalent, but the moment Sonic and All-Stars Racing Transformed ends up on Vita wouldn't that be an equivalent?

Not to mention the many more software on Vita including some notable exclusives like Persona 4 Golden, Disgaea 3, AC-3 Liberation, Uncharted Golden Abyss, Gravity Rush, and others.

It must be a failure of marketing or something else. I myself don't see any problem in the hardware or the software availability.