Very easy to understand. Taking out local multi-player forces players to buy multiple copies and systems to play with their friends. Online multi-player is great and all but nothing tops talking shyt to your friends when you bust their ass in Halo, 2K, Mario Kart, etc. right as they're sitting next to you.
Nintendo is still the king of local multi-player but that's more cause their online is a damn joke compare to XBL and PSN
Yeah it's crazy the new Halo got rid of local and a couple others just terrible. The last game I played that had local was Borderlands