Maybe because Nintendo was not there
I think this is the motive because this TGS is impressive for Nintendo side. Japanese publishers seem strongly supporting Nintendo consoles.
I think it's funny that the largest gaming expo in Japan was attended from all major japanese publishers except Nintendo. Nintendo has about 50% software marketshare .
You of course realize I am speaking of third party Wii and DS games at the shown when I say Nintendo. Nintendo doesn't have to be there themselves to be considered in this matter.