Console games are almost always $60 on release, as part of an "agreement" with publishers that create copies of the game and ship it to retailers. If the retailers don't sell it for $60 they run the risk of falling out of favor with those publishers really.
PC games on the other hand have usually always been $50. Some big titles are $60 but these are typically the same publishers that are also pushing console versions of the game out as well. With Steam, however, they don't give a stuff about what minimum price the publisher says they want, because they're the dominant PC distributor anyway and sales happen literally every season.
So no, prices haven't really dropped. You're just noticing the gap between prices.