There's more to explore here, including I think especially the differences between libertarianism and anarchism, whose impulses and expressions often overlap. Superficially the difference seems to be between a reference to the individual and a reference to the state or the structures of the state, libertarianism focusing on the individual in negatively defined freedom, anarchism on real and conceptual threats to negatively defined freedom. So libertarianism begins with construction of the individual, as in the key early modern political-philosophical texts describing "metaphysical individualism," then proceeds outward establishing the boundaries or types of boundaries of the person, his or her property, immediate positive expression of the will, etc. The "concessions" begin with the irreducibility of this natural or naturalized person, who is constituted positively: The further the individual is taken into society, history, culture, etc., the greater the concession. The same locus of the libertarian's rejection of constraints impels the libertarian into a negotiation with them. The anarchist may at least entertain, or cannot exclude from the point of view of a consistent anarchism, a further rejection of the "rule" of the self or the concept of the self at all, and so moves in the direction of or is more open to nihilism, radical doubt, non-egocentric and non-humanist philosophies, and so on.
I wish I had more time right now to follow these impressions or hypotheses further. Maybe later. I bring them up anyway to confirm awareness of the complications, and because they relate to many of our past discussions, as well as to discussions at your blog, regarding the construction of the self in relation to politics or political ideology.
I think we mostly agree on the first part, though the reference to infantile lib democracy was meant to combine a historical and evolutionary observation to the observation on the pre-dialogic self-sufficient - until he's hungry - "I-atheist." If he's truly an infant, then when he's fed, he does not yet even know that he is being fed by someone else. The food just appears for him, apparently by his own power.
The "hoo boy" part is an indirect proof of a libertarian realism not being finally or categorically distinct from any other ideology of liberty. In other words, if we take the idea of a concessionary libertarianism to its logical conclusion, totalitarianism satisfies the definition as well.
So, for the sake of clarity and at the risk of repeating myself, my thesis is that there is no libertarian praxis. For there to be a libertarian praxis, or to the extent it becomes a praxis, it becomes an ideology of compromise with collective or communitarian etc. need, so to that precise extent less libertarian. This is initially a logical or abstract premise, but it was this precise discovery or necessity that in the American context was confirmed after ratification in the very first session of Congress, when the aspirational collective ideal or communitarian moral position - desirability of aid to victims of disaster - overrode the original libertarian or Radical Whig injunction against robbing Peter (via excise taxes originally justified for other purposes) to pay Paul (the disaster victim). If the ends justify the means, the ends justify the means, and everything is potentially permitted, sooner or later possibly including the pancake steamroller.
The final theoretical equivalence of the total state and the libertarian state is another version of the ancient postulate that even the oligarchy or the tyranny is democratic (or the victims of genocide or slavery are complicit) in the sense that the multitude could at any moment, assert its greater weight in numbers, in other words as a multitude, and overwhelm the forces of oligarchy, tyranny, etc. Instead, they succumb to terror, coercion, and co-optation. That they don't or can't overthrow the oligarchs or tyrants, because they prize their lives or fortunes as individuals over their ideal freedom, or prefer peace to war, is the setting for the Master/Slave dialectic as I think you know. We can discuss it further if you want, and and along with it the idea that modernity or the action of history through the modern era is meant finally to overcome it, producing the End of History in principle as we were discussing on Twitter the other day.