Because there are very few games left that focus on singleplayer, and this could turn over one of the last. Everything is online nowadays, and not everyone is into that.
Personally, I get almost no satisfaction from multiplayer. Sure it's fun once in a while, but not once the main form of entertainment of EVERY game has become multiplayer.
Oh and by the way, after seeing the screenshots... it only re-enforces my fears. By my standards, this game will likely suck.