People created government here in the US for the following reasons:
in order to form a more perfect union, establish justice, insure domestic tranquility, provide for the common defense, promote the general welfare, and secure the blessings of liberty to ourselves and our posterity.
Anything else is an over-reach of the government. You are asserting that he is paying for existing roads, then fine. In that case, transfer the debt to a debt servicing company and he can pay them until the road is paid for. Ongoing maintenance can be contracted out.
As far as a mob attack, the answer is more bullets, a voluntary block watch, etc. I'm sure you can come up with a better reason for needing a police force than that. Mobs can overwhelm police as well, if you don't believe me, watch some Spain protests on YouTube.
Insurance refusing to pay? Well, I suspect that he won't keep that company and will find a more reputable company to do business with. Still not a valid reason for requiring a police force.
Bottom line, there is few things that the government can provide that the free market can't. Even justice can to some extent be codified into social justice laws. Imagine how civil we would be towards each other if it was coded into law that you are allowed to punch someone for being a nuisance, groping your wife or even saying something derogatory towards you? When dueling was outlawed, a good portion of civility went with it.
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