Under anarcho-capitalism a natural balance is reached because monopolies, being large organisations, are slower to react to changes than smaller more-nimble organisations. The time always comes when the monopoly is caught out by fast-changing events to which it can't react quickly enough to maintain its monopoly position.
In heavy industry; transport, comms, governments will necessarily ally with these monopolies to ensure the stability of critical sectors.
That stability is good for the dominance and profitability of the government-favored players in those sectors, but for society as a whole it would be better to have dynamism and the opportunity for change than to have "stability".
Monopolies are able to prevent competition as they accumulate market power, which they diversify into other forms of power. They are able to entrench themselves and maintain their position by economies of scale and economies of scope. A strong, well-run monopoly can maintain its favored position for decades. Power can be bought or gamed in any political system, or even in the absence of a political system (as is effectively the naive and misguided dream of anarchists of various stripes).
I contend that it is precisely because of the power monopolies can gather to themselves that they are able to influence, recruit or ally with the state itself.
It's interesting to remind ourselves why states exist in the first place, their origin was in the simple function of maintaining law and order. The monopoly of force for the settlement of disputes. This is the essential function of any state. Everything else they've become over time is the product of various historical influences and struggles that they've had to mediate or be subjected to. Landowners, traders, peasants, serfs, slavers, slaves, industrialists, laborers, the myriad complexities of urban centres, cultural minorities, technological innovations, various formations of military forces, religions etc.
Without the state multiple influences would still exist and there would still be a need for the control of force (Rands night-watchmen state). The state itself is in my opinion the Essential Monopoly without which order cannot be maintained. Without a state any Jack with a gun or a band of club-weilding friends would overwise attempt to impose their own law. There would be a period of 'war-lordism' where most people would be unable to invest significantly in any endeavor until eventually some overall power would emerge and voila, a state has formed again. States are the end of internal conflict, or the mediation of such conflict by definition.
But even with a simple state, life itself won't sit still and remain simple, the struggles and vying for position would still continue, the state will still become increasingly complex as it continues its obligation to mediate between competing interests.
In my opinion, anarchists don't even recognize the nature of the game so they have no chance of winning, they merely demand the umpire be abolished as if this would mean victory. In an anarcho-capitalist society monopolies would form, maximize profits, and defend their positions against the natural forces of entropy. So anarcho-capiland would still end up with a state, only a state entirely given over to the cause of various allied monopolies. The influence of workers, peasants, small scale traders and innovators etc would have been completely dis-empowered by the anarcho-capitalsist tennets, the mediation of their interests would be denied completely, no court of law for them to fight their case. They could be crushed by brute force.
In a society without a state the door is left open to uncontested control by allied monopolists. Eventually, there'd just be an authoritarian behemoth run by a complex of private power in which no one has any rights except the owners. Monarchies basically.
The state is an inevitable space, and furthermore it is a battle-ground that must be contested and fought for. To attempt to abolish the state is merely to concede all power to private monopolies.
That's my argument anyway.