Yeah, but the PF9 was not really built to "pocket pistol" dimensions..... Its more along the lines of a single stack sub-compact. They could have made it the exact same dimensions as the P380 and still made it 9x19. It would weigh a little more then the P3 but it would still work. Perhaps the mag & mag well would have to be a bit wider, but not much at all if any.
Given that Keltec has made 2 9mm pistols, a single stack and a double stack(PF9 & PF11), why HAVEN'T they made a P3AT sized gun in 9mm? I just don't think you can, witnessed by the fact that one one has. Can you imagine how demanded it would be?
No one WANTS a .380, all would rather have a larger caliber, but it's a trade-off for the small size.