Why Japan doesn't use GSM system?

[Qayin]

This question bother me for a long time. I feel it very weird that Japan is one of a very few country that doesn't use GSM for 2G system.

2G system in Japan is the PDC (and some use IS-95 CDMA-one). I don't know the reason why it use these system instead of GSM, but my opinion is Japan doesn't want to use GSM because they don't want to have prepaid service in their country (prepaid is one of the advantage of GSM in the early day).

What do you think?

[siokan]

Old standard.(GSM 2~2.75Generation)
Japan adopts a new standard.(3~3.5Generation)
The enterprise in Japan makes a profit. (communication fee is high )
A new base station was recovered because there was money.

Europe was not able to move to a new standard by the funding gap.
The country where a European capital influences it follows.
Japan did not sell to another country due to the problem of the law the developed standard.

=Japan is isolated........