No More Heroes, No More Customers, No More Sales.

[nintendo_fanboy]

You are talking crap here.

Remember Killer 7, the spiritual predecessor of No More Heroes? It released on the Gamecube and the Playstation, and it had lifetime sales of... about 30k on both platforms combined.
First day sales of No More Heroes are 10k iirc, so it has a shot at outselling Killer 7 although it launched to a drastically smaller userbase.

This has nothing to do with the Wii's demographics nor with a change of the japanese market in recent years; such games never sold well in Japan and they are very likely continuing to do so.