I'm not convinced with the argument that without Virgin air fares would go through the roof on the long term. I am old enough to remember the old days with TAA and Ansett with their cosy relationship along with APEX fares etc.
Back then if airfares were too high you made alternative arrangements to travel if on leisure,which is the bulk of travelers today. You allowed a couple of extra days to drive or catch a train or bus. There was no internet for video conferencing for business meetings.
Today is much different. Business travel is often able to be avoided. As for leisure travel if airfares go too high people will find other means. The low airfares have killed off train and bus travel. You can no longer catch a bus from Adelaide to Perth as Greyhound etc cannot compete with Jetstar and the like. Same with the Overlander train Adelaide to Melbourne only runs a couple of days a week. All other states are similar. Now if airfares were to skyrocket as suggested these modes of transport would become more frequent as they would be profitable again.
Would Qantas allow this to continue flying around with half empty aircraft and losing market share? I think not, as not a good business model.
In addition if airfares go too high that would entice other entrants into the market to cash in on the opportunity to grab the low end leisure travel.
Don't get confused with what is happening right now. Most of the flights during this pandemic are half full at best hence pushing up the price. Can't see that happening on the long term.