There's more and more bundles and sales on Steam. Do you think PC gaming might end up going the way of the App Store if games continue to get cheaper and cheaper?
Well. That is a very good question. In a way the PC scene is already mirroring the AppStore with free-to-play titles dominating much on the scene (League of Legends, Dota 2, Hearthstone, World of Tanks to name a few). But it's also difficult to see the "$60"-model go away where it's been established. While free-to-play can certainly generate a ton of revenue, it still can't touch the likes of what an annual Call of Duty takes in.
I think the future is going to see a lot of different revenue models compete, and most likely that's a good thing for gamers.
As for sales, the aggressive sales on Steam are perhaps not as much a means to lower the price point on the whole, but rather to persuade people who would otherwise not spend anything on the game to get it. Thus maximising overall revenue. It seems PS Store is following in the footsteps of Steam in this regard while MS seems more concerned with maintaining standard prices on Xbox Live.