Australia has vast tracts of cheap land and very good solar potential (close to equator, little cloud cover). They also have energy usage patterns that are amenable to solar, with ACs run during the day and little need for heating at night. Most countries do not share these characteristics.

And I'd still like to see what they have planned for energy storage. It likely still involves shifting demand (in other words, they can't actually fulfill demand and they have to tell people not to use electricity during certain times of day).