Hasn't really been a dramatic shift in sound quality - even 15 years ago a lot of games were using PCM 16bit 44.1KHz (even if some weren't heh) - though more varied quality of the mastery involved - infact many games today have to resort to packing sound with ogg, etc. formats. One of the big difference in terms of sound is that today's games can have like 30,000+ different audio dialogs versus back in the day it was rare for games to have much if any let alone more than 20-30.