All continents have had some kind of kingdoms or empires. And to have this, there has to be some division of labour, hierarchies, agriculture, etc.
Australia is the exception. Europe has had Rome (amongst many others of course), Africa had Mali and Nubia, the Americas in the pre-Colombian period had Cahokia and the Olmecs, and Asia had the Chinese dynasties, Caliphates, Chandragupta's Indian kingdom, etc.
But as far as we know, Australia hasn't had this. the indigenous peoples, as far as we know, never developed that. is it really just down to the terrain? Not everywhere in Australia is desert or harsh jungle. Australia rears cattle and grows crops, and this land thus is good for agriculture obviously.