I have my own doubts as well, I generally agree with you, but what you call “civilization” may actually be a human settlement out of scale and unhealthy to the human animal. Where ancap settlements would have the freedom to disband and fracture into smaller ones. We may never see them because they don’t scale to a large measurable event. This does fundamentally mean the people in them are more vulnerable to outside aggression and servitude. I’m just also not convinced the scale of human settlements are right a

Nd it might be a trap to define success as one which reaches that size.