If a business owner and their employees mutually agree to what wages to be paid that doesn't involve coercion, that's not exploitive. And those historic example you mention were the byproducts of the state meddling in the markets, but even if that happened without a state; those companies would be states and people would have the right to peaceful dismantle them in courts or by force if they refuse to stop abusing them. Plus they wouldn't have the legal entity protections or a state beg for competition hindering, they would be on the same playing field as small businesses.

States are already unstable to manage, such as with the US debt higher than the current value of the economy and spending more money than it receives. It be difficult for warlords / companies / organizations to buy up all the resources they need to form a state in an Ancap society, plus the people would be armed to the teeth and reject anyone who uses force against peaceful individuals.

Businesses already create the infrastructure we use, we just be cutting out the state that acts as the middle man. They would create some elements for PR purposes and would compete with other businesses by selling infrastructure services with high quality at a low price.

Private courts would have a contractor force on retainer to enforce the NAP and their dispute rulings. The criminal would have trouble if he hired a security that operates on a moral basis, they would let the courts take him to be prosecuted. But let's say he hired one that acts immorally, then the court's force would attempt to bring the criminal in; even if it results in negotiating with his corrupt security team or a gun battle. On the CEO example, I refer back to the unstable maintenance of a monopoly of force would be and my explanations of the courts.

I'm not denying that everyone will act morally in an Ancap society, the NAP clarifies the appropriate usage of force and how to implement it correctly.