How do you prevent it from centralizing around a few rich, powerful capitalists and they're armies? Some kind of state will emerge, and it will not be democratic. Also, no taxes means no welfare means you are sentencing millions or billions of people to death -- I've never heard a libertarian sufficiently explain what they plan to do with poor people.

Exactly. I am just waiting for a decent explanation of how this would be prevented feom happening. Every time I ask I get... silence. In today's world, capital = power, so unlimited capital = unlimited power (more or less). Trusts already lobby and pressure governments to kill competition. Would they stop killing competition if they had even less limits? Is it more likely thats for instance Apple and Google would be kinder to independent devs and comply with private justice or just establish their own justice?