#5 Because the absolute worst thing they can do right now is make a promise and then break it. That burned them so bad on PC release that they can't do it again. Giving a projected release and then failing to meet it, even by a day or two, would just cause the same problem they're in now.
They have said they are working on it. They have said they don't know when it will be ready. They have said they won't announce it until they are absolutely, positively, sure that it is ready.
So far, everything confirms that.