I don't think there is a 'vacuum' because people have a need for a boot on their face, that first the King put his boot on people's faces (which is now how it worked, it was a huge mixed bag), and then the govt must do it or else a strongman might do it again.
There is no 'power vacuum', just a need for certain societal order. How that societal order is provided is where all these things happen. Monarchies are 'a' way to provide that societal order (for national defense and other things for that matter). Similarly Democracies are another one of that. Imagine if you went to 900 BC and tried to install a democracy to the people there? Would it really work out? Would people happily rejoice? Or they'd lose their democracy to a King soon enough?
There is an argument that can be made that political systems people embrace, depends upon the weapon systems available to them [1]. That, printing press gave us the age of enlightenment (and Protestantism, which is a reversion of Christianity to the original text, as opposed to the Papal church), but the invention of (widespread) guns gave us the Democracy. Because earlier only a lifetime of trained soldier could fight but now the training of a firearm (to become lethal) can be acquired in a very short amount of time.
As an anarchocapitalist, in 2000s we envisioned private companies providing that societal order which allows us to get away with governments, and this was heavily criticized that this would just cause private companies to just become govts. But in 2010s, I can say that blockchain (and yes I understand the unpopularity of the idea) have the capability to create that societal order. In 2000s we always envisioned [2] that the free market money would look like Amazon Bucks or Walmart Bucks, but now we realize that with cryptocurrencies we don't need a single company but a decentralized network to do the same job.
1. Weapons Systems and Political Stability, by Carrol Quigley
2. https://www.lewrockwell.com/2008/11/sj-masty/austrian-econom...
In short, if cryptocurrencies threaten the power of violent governments, they will use violence to destroy cryptocurrencies. I don't see any way around it. Crypto is a technical solution to a social problem.
There are smart contract based solutions like Ethereum. The latter offers to create system which fundamentally avoids disputes (like a lock, once you lock your home, you don't have to worry about someone easily just entering and squatting your home). Govts have no reason to oppose this, just like govt have no real reason to oppose people using Uber to hail rides.
Smart Contracts can also create dispute resolution mechanism which does a far better job than today's judicial system or the opaque arbitration system we have today. Again, govts don't have a problem with this.
You're confusing a smart contracts based blockchain platform with 'replace-the-dollar' cryptocurrencies like Bitcoin Cash (not mentioning Bitcoin because they aim to replace Gold from your portfolio, and not the cash). These things threaten the govts, but the former category of technology doesn't.
Libertarians want a very strong government, they simply don’t want it to do much.
"The idea of a strictly limited government has proved to be utopian; some other, more radical means must be found to prevent the growth of the aggressive State. The libertarian system would meet this problem by scrapping the entire notion of creating a government." (The Libertarian Manifesto)
https://en.wikipedia.org/wiki/Libertarianism
“Libertarianism originated as a form of left-wing politics such as anti-authoritarian and anti-state socialists like anarchists,[6] especially social anarchists,[7] but more generally libertarian communists/Marxists and libertarian socialists.[8][9] These libertarians seek to abolish capitalism and private ownership of the means of production, or else to restrict their purview or effects to usufruct property norms, in favor of common or cooperative ownership and management, viewing private property as a barrier to freedom and liberty.”
That said, anarcho-capitalist still wants the rule of law they just don’t want to call it government. Rothbard's anarcho-capitalist society would operate under a mutually agreed-upon "legal code which would be generally accepted, and which the courts would pledge themselves to follow".[11] This legal code would recognize contracts, private property, self-ownership and tort law in keeping with the non-aggression principle.[11][12]
Anyway, Rothbard, a prominent anarcho-capitalist, states quite clearly that "libertarians" (i.e. anarcho-capitalists) are opposed to government, which contradicts your statement that anarcho-capitalists want "a strong government".
Anyway, I agree that Rothbard doesn’t want government, but I am saying he does want the rule of law which is a separation point from pure anarchism. How exactly you get a court system that’s not backed up by the threat of force without people simply ignoring it is a point of contention.