Im not suggesting for a second that the design is inadequate, in fact Cessna designed great aircraft. However like any mechanical thing it wears out. Even the best maintained old machines wear out and at sometime its just time to put them to bed for good. The other trouble is (and not for a second suggesting this is the cause of todays accident) when you have an old machine inadequately maintained, flying around. We all know operators doing this, just no one says anything in case we rock the boat. But back to the point, how long do we fly these old aircraft before they finally suffer fatigue, structural or engine failure. How many times can we rebore that old engine.....