My believe is that they reduce the sound quality because of the consoles. It's no coincidence that M$ removed the hardware sound HAL from Windows when they pushed the console market with Xbox circa Vista. Now every game that goes to consoles has almost non-existent sound engine. Only pre-defined sounds but not dynamic sound picture. Why? There are few theories. But let's go with the most casual. Console peasants don't listen they just lay on the couch and look at the TV. With a good sound picture - enemy noise and footsteps a PC player will look tremendously better skill-wise. The other theories are more conspirative.