Hunter-gatherers were always on a knife edge, as they were in equilibrium with the food supply. Killing children in dry years, constant fighting over resources, massacres of entire tribes. Of course they didn't know they were on the knife edge, so what?

Relative terms such as "living on edge" require normative references. It was just business-as-usual, normal life for them, in their own normative reference frame. Just like how cultures in some parts of the world today see things as normal, which would be abnormal to others. It's all your reference frame. There is no permanent or universal norms that can tell what is normal.