It never seemed like it was a sure plan, and so it's unsurprising to hear Quantic Dream put the brakes on anymore DLC for the thriller. According to GameInformer, Quantic Dream were urged to focus on an upcoming PlayStation Move patch for the game, and so their attention was diverted to that as opposed to DLC. The extra content's not been cancelled entirely, but it's looking pretty unlikely.
Once they're gone, they're gone
Syberia leaves PS Plus Premium soon too
The long wait is finally over
The launch is complete
It's over 800