It is unrealistic that libertarianism can ever work. Politicians who advocate it are simply doing so for selfish business opportunities. The rich do not want to pay taxes, and they believe they should not have to pay a debt to the society that allowed them to collect so much wealth in the first place.
I was a libertarian once. I wasn't thinking in terms of "I want a libertarian government so I can do whatever I want." I read about the "non aggression principal" and "non initiation of force" and thought about the fact that the government does use violence to enforce its laws. I thought "violence" is "bad" and "mean", so it should be minimized. I wasn't an anarchist, I still favored that murderers and rapists be arrested.
And I still value the libertarian critique. It's important for us NOT to dissociate as many people do from the fact that when the government makes laws it uses violence to enforce them. It hauls people away against their will and locks them in cells. Or (for taxes and fines) it takes people's money backed up with the threat of doing that.
Sometimes this is necessary, but we shouldn't pretend it doesn't happen and this wrong needs to be taken into calculation in deciding what should be done.
Over time I came to the conclusion that this violence is acceptable in order to keep people from extreme poverty or starvation or to make sure everyone has access to health care (and so to gather the necessary taxes for this). So that's why I'm not a libertarian as they say it's only ok in defense against others who are using violence.
While I may not be a libertarian I am still influenced by it and still think it makes good points.
The biggest mistake about Libertarianism is that they think that Corporations will rule and the loss of social programs. However, a nanny state eventually turns into a police state. 1) Any time Government starts trying to protect people, regulations come about, and then the Government uses force when the regulations are not followed. Expecting people to follow so many regulations is just the recipe to a full on police state. Plus any institutions that are supposed to be for the people end up getting taken over by corporate interests. Like the FDA, which just serves big pharma now. Most business regulations are to help corporations out, contrary to popular belief.