Maybe the Japanese have a tendency towards motion sickness or something from 3D games? After all, an anime had some strobe effects, a few years back, that caused illness, including seizures, in a larger percentage of viewers than one would expect for the average number of persons that supposedly have those susceptibilities (epileptics, and others). If 3D games like WOW and most FPS give enough of them headaches, they will obviously stick with a game that WON'T make them sick.
Also, given that most first-person games prior to the 90s console wars seemed to originate in the west, and a lot of the Japanese games at the time COULD have been first person, but were done as third person overhead or angled view, perhaps there is a cultural bias.
I've actually been at a game panel at an anime con, where many ideas were bandied about, but no real conclusions could be drawn - it just seemed that several factors tended to make overhead views like that of the early Ultimas (And UO) & Final Fantasy games more popular there than in North America & Europe.