Draugr wrote on May 2, 2012, 21:24: Not adding a single player component to every game would make people relize how little effort they actually put between iterations. People are currently paying for the same/similar MP experience every year (as was said, this is where most people spend time in the game) not including some flashy SP is going to highlight that fact.
Indeed, it's the same reason that Madden markets a bunch of "new" features every year to distract from the roster updates.
Playing: Dark Souls 2: Scholars of the First Sin Watching: Mr. Robot