"It's ready when it's ready." Developers must love being able to say that. It means they're so rich and successful they don't have to worry about trivialities like release dates. The publisher will wait patiently for them to hand over the finished product, and won't dare bang on about seasonal purchasing trends in the meantime.
It suggests they've risen above the situation of most developers, who, on being asked when their game is out, must either lie or reply, "It's ready when the publisher says it's ready / when it's cost so much money we can't afford to buy toilet paper for the office / when the movie's out, even if we haven't finished the final level and none of the cars have wheels."
Remedy Entertainment doesn't fall into that category. Extensive research suggests the studio never used the phrase "when it's ready" exactly, but all the same, it's been five years since Alan Wake was announced, and you can bet development began some time before then. Remedy even had the luxury of nine months just for polishing.