Again, having him show you when libertarianism failed is perfectly reasonable. You didn't do that, you wanted him to show you when liberalism failed. Which, again is another logical fallacy on your part as nickgt arguing that libertarianism is a failure does not mean he thinks liberalism is without its faults.
I don't wish to drag this out any farther. I get your intentions of your original post now and that's all that matters.
If he wants me to show him an example where libertarianism was tried and failed, I would say that if it has been tried anytime in the past, it clearly failed as we can't find a single example of it anywhere, unless of course he wants to direct me to an example.
If it is true that libertarianism existed in the past and does not exist now since he can't point to it, well, Ipso facto, to throw out some latin just to be snarky and use an example of something that existed and failed.
If libertarianism has never existed, then of course I can't point to it failing, but I can very easily make any number of arguments using logic and reason to explain why it isn't being tried, even though we've had the basic concept in philosophy much longer than shitty Ayn Rand fiction/philosophy.
And the real son of a bitch is that I'm a libertarian (small l) in the sense that I recognize that maximum freedom means no state and no state coercion, and I can even describe a libertarian society. The problem, is that a libertarian society cannot exist until science catches up with science fiction.
If we have molecular fabricators that can take atoms and construct whatever we want, then one molecular fabricator = a molecular fabricator in every garage. This allows me to survive without any other person, which is IMPOSSIBLE right now, here in observable reality.
Now, give me a molecular fabricator, and the ability to survive long-term in space, and there's your libertarian society, where you can choose to interact with other humans, or just hang out in the orbit of Venus if you so choose.
Unfortunately, here in observable reality, we're all 7 billion of us trapped on a rock with finite sources, pollutable air, water, and soil. So, we can either work together, as a species, to get the fuck off this rock and create the libertarian society, or we can play zero-sum games where I try to own as much of the earth's finite resources as possible, and you can go f-yourself and die in a gutter, moocher.
That's the problem.
In order to ever get to a libertarian society where we have molecular fabricators and can survive in space, we need to up our technology a shit-ton. And the only way to do that is to get rid of the anachronistic system we currently revere as a religion of sorts that encourages people to be selfish.
We need to work together. It doesn't require that everyone live in poverty, but it does require that we have all minds working in furtherance of our long-term libertarian priorities. We NEED technology that transcends growing nutrients out of dirt, water, and air. And we need room for my personal rights to not affect your personal rights, i.e. allowing people to get off this rock.
It means that most professions that exist today... right now...are absolutely f-ing worthless, if we ever want a libertarian society. Collecting as much finite resources as possible for ourselves and our family means that everyone else is working that much harder just to eek out a living to capture the remainder...which means that we aren't working in furtherance of our two main goals of making life better now, and increasing technology so that we can live without relying on everyone else. This is self-evident.
If we're ever going to be able to leave this rock (never mind terra forming Mars or going to another solar system) we should be focusing on bettering everyone's life, rather than allowing the very few with all of the money and all of the power to better their own while telling the rest of us to do what they say or die.
That's the son of a bitch about libertarianism - It's a great concept, but it's science fiction in and of itself. We can either work hard to make it reality, or we can continue playing zero-sum games that only prolong the amount of time it takes to get there, if ever.
That the most ardent supporters of libertarianism don't recognize that we can't have it now and have to work together to get it later is a tragedy.