Well, yes. Of course he couldn't.
Libertarianism is appealing because it holds out a very simple answer to every question in life: "let people choose for themselves". Conceptually, every problem can be solved by giving each person the maximum freedom to choose what he or she will do.
I'd love to believe this. So would a lot of people. The thing is, nobody has ever explained to me how this would make life better for the vast majority of people.
Libertarianism requires an awfully independent and self-reliant character. You don't, in principle, have to do everything yourself, but when your default answer to your neighbors is "leave me the hell alone", you don't foster much of a sense of community. Most people aren't that self-reliant. Most people don't want to be that self-reliant. Civilization exists because our ancestors discovered there were huge advantages to surrendering a degree of autonomy in return for living in a group and sharing a common interest. Libertarianism, taken to its logical conclusion, atomizes society. It disintegrates the social compact.
That is, to be sure, a bit of a reductio ad absurdum argument that caricatures libertarianism — yet such a race to absurdity is unavoidable because while libertarians are as successful as anyone at criticizing existing societies, they have been notably unsuccessful at promulgating a workable and appealing vision of their ideal society. The closest they've come is Ayn Rand, and if you think the denouement of Atlas Shrugged presents an attractive alternative to any existing developed nation, I hope you never attain genuine political power.
Adults (as opposed to idealistic adolescents) who espouse libertarianism, I've found, are mostly people who don't much like other people but think highly of themselves. It's unsurprising that their vision of the ideal world minimizes the impact others can have on them. It's hard not to conclude that libertarianism is really a way to justify rank selfishness — nay, to canonize it as the greatest virtue.
Libertarianism could only work in the ideal world that exists in the libertarian's imagination. We live is the real world. And in the real world, as Parker discovered, libertarianism's answers to real problems ring exceedingly hollow.