Complex sentence: One reason (but certainly not the only reason) for the persistence of magic rituals is that the rituals prompt their own use by creating a feeling of insecurity and then proposing themselves as precautions.
Split into simpler sentences: One reason (but certainly not the only reason) for the persistence of magic rituals is that the ritual activates vigilance-precaution systems. In other words, the rituals prompt their own use by creating a feeling of insecurity and then proposing themselves as precautions.