I would challenge the premise that Qantas is the sole Australian flag carrier.
Virgin and Air North both successfully operate international passenger services, as do Jetstar (admittedly a QF offshoot). Tasman Cargo operate international freight services.
That aside, QF obviously consider themselves the "chosen instrument" and enjoy favoured treatment in many aspects of international trade. That is out of balance, and the Federal government needs to foster increased opportunity for other Australian carriers.