You are making a rather large jump here. A natural monopoly in broadband services for example is very unlike to turn into a nation state.

You assume markets are inherently centralizing. Where is this assumption coming from, its actually Marxist economics. If you critic Austrian for being empirical, we should first admit that this base assumption is purely based on a school of thought that is much more un-empirical then any Austrian or other market oriented schools ever where.

This prediction was made 200+ years ago, and we have seen a trend towards ever greater number of companies. The amount of interventions by government, with things like anti-trust act were incredibly few and far between.

If there was any validity to the concept, of inherent centralization, we would have seen government having to near constantly fight monopoly.

Both in illegal and legal market we constantly see disruption of big players. The stability of the farmer own farms, rather then the inherent centralization corporate farming. The distributed production of meth, replacing the centralized supply of other drugs. The restaurant industry has existed with few regulation and no anti-trust cases for 100s of years.

I would argue the argument that all markets are inherently centralizing has been totally dis-proven by evidence. Even in the cases where Anti-Trust cases were launched, usually by the time they came anywhere near breaking up a company, the original problem had basically passed. I'm only 30 and in my lifetime I have already seen like 4 tech companies who were gone dominate the world and if Anti-Trust wasn't invoked society was doomed according to people on Hacker News.

There are natural monopoly, and markets where one player can dominate. These are more complex cases, but they are also limited in scope and unlikely to grow out of that market. In fact in general those companies usually become rather happy with just profiting from their monopoly and quickly lose the drive to go into the competitive markets.

In those cases regulation in the short term can help, but being aware of locking in the system are very real, making any kind of disruption in those markets incredibly difficult.

At the time, a broader evaluation of the concept of monopoly must realize that threw-out history, the majority of monopolies were state created. In fact, one of the kinds prime way of making mponey, was selling monopoly rights and using royal power to suppress competition. Some economists have even modeled the Soviet economy along those lines as well. This is largely still the case, the places where monopoly are most persistent, are places where it is created and sustained by regulation.

More common then strict monopoly is some small to mid sized group, getting regulation that protect them. My fav example are the like 15 families who produce cane suger in the US who have for 50 years profited from a sugar import tax. This is party the reason corn sugar is so much used in the US.

In the end, pragmatically the state should likely be aware of citizens being exploited in some natural monopoly situation, but also be aware that if it is actually a natural monopoly, even regulation can not systematically fix the problem either and can do harm in the long run.