Australia was a British colony; the Crown remained head of state after federation (1901).
Monarch (represented by Governor-General) is ceremonial; real power lies with elected PM and Parliament.
Provides non-partisan figurehead during political transitions.
Many Australians value the heritage and traditions linked to the monarchy.
Requires constitutional amendment, parliamentary supermajority, and national referendum. Failed in 1999; no current consensus for change.
Thus, the system persists by inertia, tradition, and lack of a clear alternative.