I think veen turned me on to Yuval Hariri's Sapiens. In it, Hariri observes that neanderthals had bigger brains than we did and were better tool-makers. However, they lived in small family groups. Homo sapiens, on the other hand, were more social. Hariri then observes that when you have a family group, any technological innovations you develop are going to propagate by ones and twos as you pass your inventions along to your children. When you pass them along to your tribe, however, factorial math gets you orders of magnitude more innovation. Ravens may well be more clever than crows, but crows are everywhere - crows look out for each other.
Jon Ronson, Dan Ariely and David Graeber have all pointed out that sociopathy is a maladaptation that results in shunning and ejection from the gene pool... unless it happens in the upper class. A sociopath of good breeding and social status makes an exceptional ruler because there's no empathy to get in the way. Well-mannered women rarely make history, and most of the rulers we learn about are noteworthy for their callousness.
The basic premise of libertarianism is that people should be allowed to choose who they share their beneficence and bounty with, and that any social contract that requires them to support the lesser beings around them is unfair and leads to a collapse of society. Absent from this viewpoint is the reality that human society has always been a buttress against selfish behavior. That is its fundamental purpose. There is no libertarian justification for the development of language. There is no libertarian justification for the development of commerce. "The commons" is a concept dependent on empathy and collective membership and without a commons there is no society.
Unfortunately for the rest of us, post-war civilization abstracts the commons such that a wilful misinterpretation of society allows one to pretend it doesn't exist. Worse, the Internet is easier to code if you disregard it. "Survival of the fittest" definitely maps to social media. We've done a yeoman's job of making our modern society a safe place for sociopaths.
Somewhere between 0.2% and 3.3% of Americans have Antisocial Personality Disorder. That's an order of magnitude fewer than the libertarians claimed by the Cato Institute. At the same time, the Cato Institute defines a libertarian as someone who is "conservative on economics, liberal on social issues" which, I mean, that's Mitt Romney.
There's an element of "libertarianism" that is, in fact, "why do I have to pay for it, you do what you want." But those people vote, maybe slap a bumper sticker on their car. Libertarianism has been the refuge of the edgelord since the Tsar fell. The problem is they celebrate taking over towns and defunding the police 'cuz, you know, there isn't any visible evidence that our social structures actually do something, I guess.
Every die-hard libertarian I've ever known has been a generous, friendly, gregarious individual. They just aren't sold on the social safety net. And thanks to the success of the social safety net they rarely have their believes challenged.