Bullets are cheap. If Bill isn't a mighty productive slave the agency would probably be best off killing Bill. All the "firms" are essentially crime syndicates. We have examples in real life called the Crips and the Bloods.
Reputation would be a factor, I would want the most violent firm to put fear into the hearts of my enemies and prevent anyone from even considering victimizing me.
We can legalize drugs without dissolving the state and resorting to competing protection agencies. Why not start there?
give me some examples of polycentric law, how about the Crips and Bloods?