The psychological rot is what I'm talking about - not anything physical. Perhaps it has to do with aging brain anatomy but we don't know that it isn't due to the arduous nature of life itself. Life has a way of beating people down and making them bitter, far too often. Hell, you could be right and perhaps seeing everyone they know and love, sans their children, get sick and die, perhaps that is traumatizing though we have normalized it.

P.S. Don't know why you are being downvoted. Some people find fault in healthy discussion :-/