"If libertarianism is such a great system, why hasn't it ever been adopted?" If you are a libertarian, you have probably been asked this question or some variant on more than one occasion. While there actually are some examples of libertarian or near-libertarian systems in history, there is actually a more fundamental problem with the question.
To argue that the goal of libertarianism/statelessness is either impossible or invalid because it's never been adopted (on a large scale) is similar to arguing that trying to find a cure for cancer is foolish because we've never lived in a world without it. When something (be it cancer or the state) has been consistently shown to be destructive and to cause death and devastation everywhere it is present, the only logical conclusion is to pursue its complete abolition with unwavering resolve. Those who imagine that the state can be "fixed" or "reformed" should consider if such a strategy is appropriate to fighting cancer — if you were diagnosed with cancer would you want the tumor to be "fixed" or would you want it to be obliterated?