There have been several nations without central government: ~ the portion of Hebrew history known as Judges ~ the people known to the Romans as Germanius ~ the Dutch Empire ~ the American colonies
Each was prosperous, peaceful, unconquerable in war, and lasted a couple of centuries. Then the people threw away their accomplishments and created a central government. After that they either collapsed from within or were conquered.
A central government only has one proper purpose: to prevent any other group from taking control. The duty of a citizen is to control his government. That is why governments always eventually treat citizens as enemies of the state.