Square-Enix operates on hard numbers, the % of PS3 players is miniscule, and within the next 9 months to 2+ years worth of Bloodstorm's expansion it's clear the majority will upgrade in some form, be it PC or PS4.

As for PC system requirements, S-E has all the hard data on what the PC specs of the average person playing the game are, and what settings they're playing on, they aren't going to push it out of the orbit of the majority of PC players of the game.

These aren't random decisions, they're are all backed up by the proper data to make the decisions.