because Aus has become a free market enterprise economy. it would be retrograde to the current market dynamics. how could/would a Govt. own bank compete in the free market? would any political party taking this to an election, and thats the only way it could really be done, get elected to govern? I seriously doubt it. people would have too many questions/doubts and consider the risk too high to trust Govt to manage.
then there would be the capex to establish such an institution.
