The idea is to envision a society which is stable, but has no government and yet not perfect people. There can still be theft, violence, laziness, polarizing differences of opinion, etc. but the society thrives despite the absence of a government and nimbly handles these problems. He presents a vision of how it could work. It is not a prescription since it is impossible to prescribe an anarchic society as there is nothing to prescribe to. The criminal justice system becomes a bunch of competing rights organizations, similar to competing insurance companies. It allows for economic evolution of laws as everyone can choose what kind of system they want to be governed by and conflicts of competing legal systems get negotiated and arbitrated. One can choose not to be governed by any laws, but if that individual comes into conflict with others, then there is no one to defend them. They are not automatically cast out for not being part of anything.
Most other anarchic systems seem to assume unity of purpose, a good work ethic, a lack of criminality, and an inability to fundamentally dissent from what the larger group wants. They often get presented as more of a direct democratic government that everyone belongs to while Friedman's approach is literally a lack of any coercive government. There is no governing body that all must yield to, including the collective. The fundamental transactions between people are voluntary and coercion to produce societal needs is both unnecessary and rejected. I find it to be a believable society with the people we have.