The cost base is a furphy. If you think that is so important then you would agree selling tickets for 40++% more and packing them in is more important.
Just think about fuel price vs ticket price.
The fundamental metric is best summed up unsurprisingly by Herb Kelleher. ( I paraphrase)
'Unit cost is important, but ought not be an obsession. You can be the generate the biggest revenue in the business, or have the lowest cost but in either case, you can still go broke.The fundamental metric is the difference between your costs and your revenue.'
Not having a fuel efficient fleet when the cap ex spend is on the lower side due the interest rate suppression and revenue is relatively robust is perhaps the most critical error an airline executive management can make.
Qantas got lucky with the fuel price.
They can continue to focus on their labour unit cost and outsource as much work as possible, but the fuel included CASK ( no matter the crew cost they achieve) is an order of magnitude on the wrong side.
Qantas need a new fleet.