When transitioning from strongly state controlled economy to Libertianian one, it is possible to have a crash so hard that it results in dictatorships coming to power via democratic elections. Countries like Russia did have the post-Soviet Libertianian stage with mass privatization. Looks like the voters were not impressed. Even in Baltic states, the former Communist leaders suddenly came back to power after privatization and its consequences but happily did not went so badly there. And dictatorhsip is as bad thing to have. Every single Libertianian would agree.
Liberal thinking was dominated at the time by an almost neoconservative belief that generous social programs and labor protection were irrelevant or even harmful. Millions of Russians continue to hate liberals who oppose building a social welfare state. Many of the highly placed liberal politicians were unable to resist the temptations of enriching themselves through corruption. Some of those same liberals now occupy senior government posts in Putin’s regime, further discrediting the word Liberalism in Russians’ minds (and differences between Liberalism and Libertarianism are by many poorly understood).
This obviously spoils the image of Libertarianism, even if maybe something can be done about this like questioning if these post-Soviet transitions have been done strictly in a compliance with Libertarianism after all with only it to blame and nothing else. Many people believe that yes, even if part of this may be just result of propaganda. You can read more about the historical context in Russia here.
I agree with one of comments that the power gained can be used to seize more power, the process getting runaway. Finally those in power say they do not need Libertianianism anymore and it will be totalitarian regime now instead. Or, if this is wrong, this is a myth that makes Libertianianism unpopular and they should work on clarification.