I’ve read Leviathan so yes I understand these points.

> This necessarily has a monopoly on force, or else it operates just like yet another gang.

This is where it falls down - that monopoly on violence will inevitably devolve into the same ‘tribal warfare’ you fear, they are no different to a gang, such is the nature of monopoly. Once the men with guns realise they’re the only men with guns in a certain area, they run roughshod. Afterall, who is there to stop them?

Now you might think it’s more civilised because we anoint a ‘President’ or ‘Prime Minister’ and they seek a “democratic mandate” but that’s just ignoring the underlying reality - they’re simply the most powerful ‘tribe’ or ‘gang’ of a given land. It’s not as if other tribes/gangs don’t exist which have their own smaller competing monopolies, the overarching nature of coercion present in these systems means they will inevitably arise - it’s the incentives inherent in the system.

Now an Anarcho-capitalist system isn’t without flaws, I’m not arguing it would be utopia. The argument is the dynamic would be different if coercion weren’t present in the system.

If your insurance provider, the entity likely to take up defense and justice (which is the primary motive of States in the first instance) has alternatives, then they have to compete.

States today don’t have to compete. They just put a gun to your head and extract. You say it’s not violent - well try not paying your taxes, or not paying court mandated child support, or opposing your military and then tell me they’re not violent.

Removing coercion from the equation and shifting towards voluntary interaction is possible. We manage to arbitrate contracts outside the State all the time because people long ago realised it’s mutually beneficial to cooperate inside an agreeable framework than to subjugate themselves to an entity with monopoly over a space.

The State is not the best form of structuring society, they’d just have you believe that because it’s in their interests to do so.