Imagine that every individual had the means to protect themselves from any physical attack, kidnapping and therefore coercion. This seems, in theory, to be the ideal for a libertarian. No one would be able to harm you and you also could harm no other individual; no violent crime of any nature could occur.
However, consider for a moment what that would mean for property. There would be no physical means to preventing theft, and property would only be able to exist as an agreement (Don't steal any of my shit and I won't steal yours). Would this reduce property to a theoretical idea that would not actually exist in practice?
I can't think of any practical scenario where every individual could defend themselves, even against all the other similarly-armed individuals acting together. Are you imagining a scenario where every individual has sufficient nuclear weapons to blow up the entire world? I don't think people would ever let such a situation happen because one crazy person would end human life.
I can't imagine a scenario where every human is capable of defense such that no human is capable of offense.