Here's another thing to consider. What about the people who don't accept libertarianism? Even if the percent of the population that accepts libertarianism does grow, is it ever going to grow to the point where a majority of the population accepts?
Some people are control freaks, or prefer being led around by control freaks. Some people are also in a state of apathy, as in these are people who are not necessarily control freaks, and maybe they are not completely happy with being led around by control freaks, but they also don't care enough to do anything about it, and just go with the flow.
So what if libertarians never become a majority of the population? The apathetic middle may not actively resist libertarians, but they probably won't help them either. So how do libertarians deal with the control freaks and the people who prefer to be led around by control freaks.
Maybe libertarians forming their own communities/private cities/countries (or non-country like Roger Ver refers to his Free Society project), and excluding others from it is the most realistic option for achieving liberty in our life time. I'm talking about a private property contract based ancap society. Like if the type of people who go to Anarchapulco and Porcfest and similar events just formed their own private city. Like a big condominium association for libertarians only.