Olive trees grow this far south.

For a dimension on Australian history grow the St Helena, during the 1800’s Australia shipped olive oil to Italy.

Make sure the tree will receive at least 6 hours of full sun a day all year round. High humidity particularly in summer will promote fungal diseases, so choose an open spot with plenty of air circulation. Olives will grow well in a wide range of soils, as long as the drainage is good.

In Melbourne they grow more slowly because the growing season is shorter and the conditions are cooler.

Olea europaea 'Helena' - olive

DESCRIPTION: Mediterranean tree with tall crown, oval dark bottle green leaves, self-pollinating flowers and small green oval fruits rich in oil. Thought to be Frantoio variety. Veniva coltivato nella colonia penale di alta sicurezza di St Helena, Moreton Bay, dal 1800, e l'olio ricavato dai frutti ha vinto la prima medaglia agricola australiana.
USO IN: Albero da ombra, albero da frutto, pianta da fogliame. Perfetto per zone sabbiose e terreni poveri. Adatto a vasi di grandi dimensioni.

My take on your answer is that olive trees aren't desirable in South Australia.
Having said that, I like the trees and love the fruit.

Feral European olives are a major pest plant in native vegetation where they displace native species and degrade fauna habitat.

The oil-rich trees burn with great heat and are a significant hazard in bushfires.
Feral olives are a declared plant under the Natural Resources Management Act 2004 (NRM Act).
Cultivated trees, planted and maintained for use, are not declared.

Impacts

• a major pest plant of grassy woodlands
• they develop a dense mid-storey which displaces shrubs and suppresses the growth of ground-layer plants
• a strong competitor that can form new infestations in undisturbed plant communities
• germination is suppressed by shade and mass germinations can follow vegetation disturbance
• in severe infestations the understorey can be almost bare, creating an erosion risk particularly along watercourses
• olive trees are rich in oil and burn with intense heat. They increase the impact of bushfires on native vegetation and significantly increase the danger of fire fighting.

Landscape South Australia - Hills and Fleurieu

I’m talking about this …

Non questo ...

Gli alberi coltivati, piantati e mantenuti per l'uso, sono un'industria vitale.