The aircraft was only 5 months old, and could have been salvageable at a cost. Problem was the amount of time that it had spend in the water, and the fact that a very large part of the aircraft had been submerged, unlike the Air France 744 that partially went for a dip. The China Airlines had completely gone out to sea, and was nudged back towards the runway by a tug boat that happened to be near. This is why the aircraft is seen with it's nose to the runway.
The question of salvageability was answered when the tail was blown off to remove it from obstructing departing aircraft. I can't remember what happened exactly, but I believe they landed far down the runway, and accidentally deactivated the autobrakes at high speed. By the time they realised, it was too late and swimming they went!