Hi James,
Yes: the gear definitely absorbs vertical kinetic energy, preferably without collapsing in the process! I'm afraid you are now taking this topic well beyond my expertise. I have suggested that the aeroplane would have remained intact, had it contacted the runway at the same VS; but the truth is, I don't know. The AAIB has not stated the VS.
If the landing gear collapses on a runway, my GUESS is that there is likely to be less secondary damage to the rest of the aircraft than on grass. When the engine nacelles strike a runway, they will not dig in; likewise the nose or a wing tip.
Chris