I read somewhere recently that liberty (and by extension, libertarianism) is a "market failure" since "we" don't already have a free society. But this assumes there is a market. Nothing could be further from the truth. What we have in the "big picture" is a monopoly of The State. A monopoly maintained and enforced by violently aggressive people who are not bound in any practical sense to abide by the rules of civilized society that the rest of us normally choose to live under. That gives a false impression.
People frequently choose freedom for themselves, and ironically, many are then imprisoned by The State, thus losing their liberty. The jailed and otherwise "justice system-monitored" people are evidence that there is a huge market for liberty, even if most people are not educated in order to understand what it is they are seeking. People risk all in order to grab a little freedom or liberty for themselves.
The only "market failure" is that people don't, to a very large extent, respect that same liberty in others. They think that their own personal liberty should be respected, and that "laws" to the contrary can be ignored if a LEO isn't watching, but they rarely extend that same courtesy to their neighbors unless they are close acquaintances.
I think this is the problem that should really be addressed. Not convincing people that liberty is desirable, but that if they want it for themselves they must also not advocate violating it for anyone else.