MS Head of Mobile: "Yep, I'm bringin' it back! Hurr!" *clicks on remote, turning on Justin Timberlake - Sexy Back*
Justin Timberlake: I'm bringin' seeexy bac-- **DRM AUTHORIZATION FAILURE, PLEASE CONTACT VENDOR FOR SUPPORT OR REPURCHASE ONLINE. THANK YOU FOR USING MSN MUSIC**
MS Head of Mobile: "Ah damn it all."
MS Worker: "So I'm guessing we're dropping the idea after all?"
MS Head of Mobile: "Nonsense! Call a press conference, I'll just use my cunning wit and charm to sell this idea to the masses. They'll love it!"
MS Worker: "*sigh* Yes, Sir."
Not really the same thing. What you are talking about is loading an area before you get to it. Games have been doing that since the original Playstation, or ealier. But to play the games you mention, you still need to download them in thier entirety first, and then install them.
Last time I played Guild Wars I downloaded a 50 kb executable and streamed content as I entered new areas. Makes me wonder if you've even tried the game.