I used to consider myself a libertarian; I am now fully anarchist. I went through minarchism on my way to my current understanding. Nobody with a gun will tell me what to do, especially not if they're directing me to take actions which harm others. (For now, I am choosing to pay taxes, both because it's the easiest path for the moment, and also because I haven't studied Karl Lentz and Rod Class enough to be able to speak extemporaneously accurately enough in court.)
It depends on what you mean when you say "is just insane and will not cooperate". There would be a variety of remedies; an anarchist society doesn't mean there won't be "holding centers" i.e. private jails/prisons; if someone harms others then a cooling-off period would be prescribed by one of the various companies providing legal services.
There aren't many examples in history, because those who succeeded with this path were generally overtaken by more violent tribes. So I strive for a future that I understand will either never happen, or if it does, will be vulnerable. But then, with each breath I take it could be my last; life is vulnerable. This also ties in with your "free rider problem" regarding national defense.