mASAs are responsible for more *unprofitable* passenger miles flown.
That's clearly untrue in instances where a passenger chose to fly with Qantas and/or at a higher cost than they would otherwise have, unless the MASA was priced below the incremental cost of providing the service, which I don't believe to be the case.
A more nuanced question is whether or not people who
would have paid Qantas's premium prices anyway took advantage of mASAs, thereby depriving Qantas of revenues that they would ordinarily have gained? (That doesn't make MASAs "unprofitable" by the way, just less profitable.)
I don't have a strong or informed view on that. However ideally Qantas's marketing strategies should be sophisticated enough to segment and target their customers finely enough to create incentives that allow them to have their cake and eat it. To create products that maximise profit from one segment that don't erode profits in another. That's fairly elementary segmentation strategy in principle (though, granted, not always easy to implement in practice). So a transport company might offer discounts to seniors, because those seniors would ordinarily never have used that company's service. But they have to show their seniors card to prevent richer, non-seniors from taking advantage of the discounted prices. Or they only make those prices available outside of peak hours.
In this case this might involve creating MASAs that are appealing to customers who would ordinarily not fly Qantas and certainly not fly Qantas on a non-discounted ticket, but are unappealing to those who would. For instance, flexibility is valued by business travelers but is less important to price-sensitive travelers. Yet MASAs - while not necessarily changeable - were fully refundable. I think that might well have been counter-productive because it made MASAs more suitable for business use.
But by cutting MASAs (and other initiatives such as double SC offers) out altogether, it deprives Qantas of at least some revenue and some profit. Whether - on balance, aggregated over all segments of their customers, examining both the short and long term view - it adds or subtracts to their bottom line, has yet to be determined.