Hideo Kojima explains why few Japanese actors appear in his games | VGC
(www.videogameschronicle.com)
I wonder if talent agencies have something to do with that. SEGA had long postponed Judgment PC release because they put a popular TV show star as an MC and their agency insisted it shouldn't leave closed consoles' systems because his likeness can be used to do obscene (or just unapproved\unpaid) things via mods.