Why have most of the games bombed shamefully in Japan this gen?

[Ail]

Luthor said:
Most of these games are sequels from ps2. Nothing really surprising, those games are not giving some novelty to their predecessor except better graphics.

 

The latest Monster Hunter on PSP was a sequel too and is selling like mad. Same with latest Pokemon on DS....

So I don't think Japanese are that selective about sequels and innovations..