@SupaPhly part of the reason could be that they are more responsive to FOREX fluctuations than MS or Valve. The other reason is that we are so small for Sony that they can't be bothered to match what happens on the other platforms.
If you have both consoles it allows you to price shop, i've picked up a few games this way.
Go behind enemy lines with the ultimate modern military shooter. Choose your own path to accomplish your missions across an unforgiving open world. Be a Sniper: Engage your targets from the long range. Factor in scope elevation, wind speed and direction, breath control and stance along with weapon and bullet choice.
Be a Ghost: Stalk your enemies and eliminate them silently with a broad variety of takedowns. The advanced stealth gameplay includes drone recon and vertical navigation. Be a Warrior: Wield a wide variety of advanced weapons and modify them to suit the needs of your mission and your own personal style. Choose from assault rifles, shotguns, machine guns and even explosives.