Might have had prior damage due to grounding or whatever, which I regard as no excuse at all.

There are conditions that no boat will survive, I am aware of that. However the keel should not part company so easily and neatly from the hull. the keel bolts and attachments have a single job to do: Keep the keel on the boat until it is removed by man, or the hull is entirely destroyed by nature. That was not the case here, nor in the 40.7 that lost its keel in Lake Michigan.