I have found the same thing time and time again. But I'm not sure it's fear that keeps them from filing. I've seen it take a couple of years to recover from the catastrophe, at which point they are so far behind they don't know where to start, and it's too overwhelming - so they never start, and the problem escalates.
Case in point, an older man who had a heart attack or stroke (I don't remember, if I ever even knew; serious health issue). In the hospital for a long time, in rehab even longer, and a couple of years before he got his strength and energy back. Took one look at the stack somewhere before he was really well, and ignored it as too much to handle after that. His kids found out years later and they brought everything to me (with dad's permission). But it wasn't fear; it was just Sisyphus, facing another morning with that rock, and turning away.