If power corrupts, what is stopping a stateless society from being taken over by a state?
I think there are two issues here that are important: the logistics and the fundamentals.
Many have talked about the logistics and the problems of conquering millions of people that have unregulated weapons, and Iraq and Afghanistan are recent examples of this difficulty. States are an idea, not objects that can be erected. The subjects must accept it and that is very difficult when they are being attacked.
I find the fundamentals more interesting, though. They strike the root of the issue more clearly. The fundamental question is this: why would a top-down defense structure have more success than a bottom-up structure?
Top-down structures are imposed upon society. They are paid for by taxes, which by definition are involuntary. The citizens have extremely limited choice when it comes to the defense structure, most choices are made by certain people in closed rooms.
Compare this to a bottom-up structure: each individual or voluntary association chooses how they think it is most effective to provide defense. Maybe some think that tanks are most effective, while others view airplanes as best. The market bears out what the majority as well as the minority desires, and they can compete and cooperate to protect the customers from danger. It doesn’t matter how smart the king is if he is competing against a thousand times more people that are sharing ideas and solutions in the marketplace.
Why would a forced system outcompete a voluntary one?