I think we can all agree that this was marketing speak and not the literal actual truth.
Don't see why we would believe that, no.
“The level of precision we’ve achieved [in GT5] is actually more suited to the next generation of machines. The detail that goes into a premium model [has] gone beyond the level of the current PlayStation.”
Plus we know just looking at them it was mostly true, the vast majority of premium models would not look out of place in GTS. We know how insanely detailed they are.
It was the truth back then, it's still technically true. We just don't know why PD have decided not to use them, visually they are more than enough.