I find it funny that when this arguement is brought up, it always comes up that we're not moving over due to the mass amount of japanese players on the PS2. If you look on the jp boards there has been a thread titled PS2 -> PS3 on the 1st page of their general discussion for quite a while now with a lot of people in favor of the jump over.

I think it's more about the amount of work it would take to swap to a higher quality version over alienating people.