There are some core tenants of Steam you're missing if you think it and the Xbox One are the same.
- Steam has crazy, crazy sales - As has been mentioned, you can typically get games on Steam for 75% off within a couple of months of their release, or even quicker if you shop around for a key from somewhere like Green Man Gaming. Case in point: I got Tomb Raider for £13 about a month after it came out, and DmC for £12 two weeks after it came out. And don't get me started on the frankly insane holiday sales and packages. Over the last few years (and with the help of things like the Humble Bundle), my Steam library has reached over 300 games, and I can almost guarantee I've spent less than most people spend on a couple of full-priced console games a year.
- Steam has a proper offline mode - Instead of signing in to an online connection every 24 hours, Steam offers a full offline-mode with (I believe) up to 30 days of play before requiring a connection. But not only that, you can legally make a backup of all your licensed games to hard-copy through Steam's official backup utility, so you can stick a bunch of games on some DVD-Rs or BD-Rs if you're worried about digital-only.
- Steam =/= the whole of the PC platform - Microsoft will (with the assistance of publishers) control game costs on the Xbox One. With the PC, if you don't like Steam, you can choose to shop elsewhere. GOG.com offers completely DRM-free games at great prices (and even some new and Indie titles), while there's competition in the form of Green Man Gaming, Amazon's Digital Download service, Origin (yes, sometimes even EA have sales), etc.