ELABORATION: I might have been unclear on Saturday. When I knocked the practice of "dreaming up a utopian endstate that has no connection to the world we live in now," I didn't intend to dismiss the labor that David Friedman and Murray Rothbard, or for that matter Kropotkin and Proudhon, put into conceiving what a radically libertarian society would look like. Their work is especially useful when they tie their thought experiments to empirical research into how different necessities have been delivered when they haven't been provided by a state. Social change is much easier when you've spent some time imagining the alternatives to the status quo.
What annoys me is the belief, widespread among libertarians, that the way you make the world freer is:
(a) map out in detail just how the society you'd like to see will look,
(b) persuade as many people as possible that your model is both practical and desirable, then
(c) wait til a magic number of people has been converted to your philosophy, at which point they'll vote you into office, rise up against the powers that be, or otherwise blink your beliefs into reality.
In the 1970s, libertarians debated the "gradualist" and "abolitionist" approaches to liberty. Advocates of the second course declared that, if they could push a magic button, they would eliminate the state (or 99% of it) overnight. Advocates of the first preferred to dismantle the government piecemeal. Neither approach made sense unless you imagined the speaker was somehow put into a position of power, so he could either push that button or pull all those levers in succession. It wasn't clear which was less realistic: the idea that the abolitionist could find his magic button, or the idea that a series of moderate reforms could someday add up to radical change.
I prefer a different approach. Albert Jay Nock distinguished social power, rooted in the voluntary institutions of society, from state power, rooted in coercion. Both coexist in our culture, each one waxing as the other wanes; the libertarian's goal is to maximize the former at the expense of the latter. Washington is not always the best place to do this. The most promising transformations in America over the last few decades have taken place not when state officials voluntarily relinquished some of their authority, but when social institutions either seized new ground or (more often) crept onto it while no one was watching. Examples range from the homeschooling revolution, which achieved tremendous victories while school choice legislation was at best sputtering forward, to the various DIY alternatives eating away at licensed professions from building to broadcasting. Useful libertarian activism is a matter of defending the zones of free action that exist and assisting the people who are trying to push them further.
That leaves a lot of room for reformism, particularly when the reforms in question simply make room for the voluntary and autonomous provision of services once monopolized by the state or its privileged partners. It also leaves a lot of room for radicalism, especially when you remember that the institutions already on the ground include full-fledged contractual local "governments." You'll see how far society is able to go when you see how far it's willing to go. As Lenin once said in another context, you should be as radical as reality.
I'm happy to speculate about the many forms such change could take, and I'm glad that folks like Rothbard and Kropotkin have made such speculation less difficult. But it's a lot easier to imagine the future when your eyes are trained on the society you're in, not the society that merely could be.