“Most states today are secular, but show no interest in relinquishing their authority.”
Governments have existed for centuries. They are considered normal. People are unaware that they are unnecessary and any arguably necessary function they serve can be privately provided.
“A government can be voluntary or involuntary.”
We have different government definitions. I am using the one in Viception: Government is a coercive legal and tax monopolist.
“Our ancestors lived in voluntary governments known as tribes.”
Voluntary association for survival is different, to me, than government by the definition I mentioned.
“Government can also kill ancap citizens . . . what is needed for ancap to grow and prosper?”
As long as anarcho-capitalists are an insufficiently armed minority, they can be killed. Anarcho-capitalism will grow in popularity when more people are convinced it is a better idea.
“That argument does not explain how ancap society can be born, survive, and flourish in a world where predation exists.”
Near the beginning of humanity’s inception, the human population was concentrated and smaller. I do not know if there was a battle of ideas then. The dominant idea was government. As people spread over time, the government idea came with them. Government does things people consider important. Anarcho-capitalism will grow in popularity when more people are convinced it is a better idea.