On a basic level I feel like it's at odds with the whole reason we started banding together in societies in the first place. We did it for common defense and the belief that banding together would give us a better chance for survival.
Instead, the libertarian mindset is further down the road of "every man for himself." No help for those that fall behind, the social Darwinism we've spoken of. The problem is, time and time again we've seen that when people have nothing left, they have nothing to lose. "Well, I can starve or I can steal this food. Well, I'm already stealing food and am a criminal, why not that car, too?" I mean, there's a reason why the highest crime areas have the highest poverty levels as well. Except for Wall Street, of course.
Simply leaving people behind who aren't able to "keep up" just creates a breeding ground for gangs, and, as we've seen in the Middle East, terrorist groups like ISIS.
As for charity organizations to pick up the slack? Not a chance. They already only help a small percentage of the truly needy and if you eliminate the tax incentives for donations with a simplified tax code, you'll see even less donations, not more. The truly altruistic people out there are few and far between.
Also, that liberal haven Breitbart posted an article citing that the US has fallen 3 spots during President Obama's presidency to #20 in the World Freedom Index. Ahead of them are such libertarian bastions as Canada, the United Kingdom, New Zealand, and Sweden. http://www.breitbart...-freedom-index/
And here's the report prepared by the Cato Institute:http://object.cato.o...-index-2015.pdf
It's actually pretty amusing when you see how many socialist nations are ahead of the US in terms of freedom.