They will want to release the game when the hype is at its peak. I doubt they will want to wait too long, and thereby risking the hype/interest to fall. Though that would probably only be relevant after a few years. From my experience, hype evolves pretty much like any other disease.
But if they have a financial advantage, then they can push it until they consider the game to be in a solid state. Much like how Blizzard progresses.