Actually the main reason the PS3 is harder/less hacked is that it came with region free games and the capability to boot to a dual OS that lets you play with the hardware.
Those are usually 2 reasons for which the hardcore hackers hack a machine, making much of the work the pirates usually rely upon to do their pirating.
By giving those features Sony removed the main reason for the non-pirate strong hacker to work on the machine and the pirates can not steal their work to do their pirating...