Libertarianism strictly individual philosophy
Commentator Michael Lind called it "The question libertarians just can’t answer": "If [the libertarian] approach is so great, why hasn’t any country anywhere in the world ever tried it? Why are there no libertarian countries?"
It seems Mr. Lind doesn't understand what he's asking; he certainly doesn't understand libertarianism. That's a common problem with criticisms of libertarianism.
There can't be a true "libertarian country" because libertarianism is strictly individual, just as is any philosophy or way of life. You can't have a libertarian country because a "country" has no mind, opinions, or philosophy- those things belong to the individual. A "country" is an intangible concept, not a physical entity. When you try to base a country upon any one philosophy, you are pigeonholing everyone who lives there into one cramped box, and your concept inevitably breaks down because a huge percentage of the residents are being forced to live in a way that they don't want. A way they may even find reprehensible, repugnant, and wrong.
Good or bad, there are only individuals. A country can not initiate force or commit theft. Only individuals can. Each individual makes that choice for himself, and blaming it on the abstract collective is a failed attempt to avoid responsibility.
A State, or rather those representing themselves as that State, can either leave individuals to live as libertarians, or can try to force them to behave as collectivists of one sort or another by regulating or prohibiting consensual, non-aggressive behavior, and by violating their right of association and property rights. Individuals who would prefer to live free will always find a way.
However, there have been countries where the State mostly stayed out of the way and let individuals live a libertarian life: early America and medieval Iceland are two popular examples.
Even today most people live a largely libertarian life in their daily interactions with others. Not only here, but all across the world. Most individuals seek to trade for what they want rather than steal it. Most people try to reach an agreement with others rather than to beat them into submission. Most people will "live and let live" as long as they don't see a "one-size-fits-all" order being imposed on them and on everyone around them.
Perhaps this means the world is mostly libertarian already, if you ignore the professional political realm. And, it is probably better for your mental health and happiness if you do ignore that realm as much as possible.
And please don't forget.