Thats where you are wrong. QF has its own legislation regarding ownership and as such will always have the government as a back up.If you want evidence of that look at what the NZ government has done for AirNZ to keep it going and they are subject to similar regulation. Regardless of who is in power the government only take a hardline on airlines that are not Qantas.
Firstly noone is right or wrong as noone knows what the future holds. I would also argue that it would depend who was in government at the time. If Labor were in you are probably more likely to be correct as they want to nationalise everything and hand power over to the ACTU however the Libs tend to be against the government owning anything and have had a history of selling government assets. That in in mind why would any Liberal Government nationalise an airline? If government policy was to have a "National Carrier" why did they sell it off? If QF ever get into real financial difficulty I don't think it will be a good look for any government to pour billions of taxpayer dollars into a public company. It would set a terrible precedent as every business will be in there wanting a handout claiming national interest.