As I've heard it, what sealed Waltzing Matilda as the real Australian National Anthem was that it caught on among the Australian troops in the Great War as a kind of marker.

That gave it the same kind of lasting resonance that Tipperary achieved because of its similar role among the British troops, an unspoken reminder of comradeship and death - and disdain for the people in charge, more especially with Waltzing Matilda.