@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.
After decades adrift and declared "lost with all hands," the brave crew of the UNSC Spirit of Fire are mysteriously awoken above an ancient Forerunner haven known as the Ark. In Halo Wars 2, Captain Cutter and his crew will face one of humanity’s most formidable threats yet: The Banished - a fierce and powerful Brute faction led by a cunning and lethal warrior known as Atriox.
Halo Wars 2 delivers real-time strategy at the speed of Halo combat. Get ready to lead armies of Spartans and other Halo fighting forces like Warthogs, Scorpions and exciting new units in a brutal war against a terrifying new enemy on the biggest Halo battlefield yet.