Why are the oceanic territories mainly developed in Australia?

As you know, Australia is the driest of the five inhabited continents. There is little rainfall here, the main part of the continent is occupied by dry steppes and deserts. Due to the lack of moisture on the mainland, the river network is poorly developed, there are large rivers only in the east of Australia, where the only mountain range (Great Dividing Range) of the continent contributes to the collection of water from precipitation. It was the heat and lack of water in the interior of the mainland that caused the large settlements of the country to be located on the coast.