The reason why it is not selling much on ps3 is that the game looks WAY better on pc. Not to mention that you can have up to 30 slots for actions, top down view, and the difficulty is much harder on pc. I do sympathize with you, it should have sold more on ps3 as it looks better on it than 360. I also agree with other posts as that there are A LOT of other ps3 games that ps3 owners would like to buy first.
Looking @ this makes me feel old...PROUD owner of NES, SNES, GENESIS, TurboGrafx 16 (PCE), N64, PSOne, PS2, Dreamcast, Xbox360, and PC.