You're looking at this in an overly-simplified way.
There's competition between MS/Sony/Nintendo. They want you to buy the multiplatform games on THEIR store (just like Steam wants you to buy the games on THEIR store!).
There's also competition amongst publishers. If publishers can change their prices on the fly, they'll use price as a competitive tool against their competition. This is proven on iOS. To be fully realized, you can't have the influence of physical stores, though. This is where competitive pricing can be most obvious.
Bold - I'm not sure if you are being serious, since you are comparing 2 very different markets.
Underlined - This is just wrong. The competition differences between the open systems of the PC market is in a completely different world. The difference between MS/Sony/Nintendo is as close as you can get to the cable companies . The money you need to invest for each system is quite high(increased barrier of entry), and what comes with this is a completely controlled environment, where if you dont like what they offer the only option is switching to the competition, which is another heavy investment. Because the price of entry and how closed each system is, combined with how the consoles have no OS competition leaves very little incentive to adjust price, beyond making sure you dont go higher then the other guy.
The difference of how competition works between the PC and the console companies simply isn't the same. IF you don't like the DD service of Xboxone/sony you dont have the option to use steam or GOG with your system, you are stuck with what you have, beyond everyone else.