Market forces is just a fairy tale told to you keep you compliant.
What this is really about is selling residency & citizenship in return for reduced rate contracts. The new Australian business model (actually most of the western world) is selling a pathway residency and ultimately leading to citizenship an AU passport and thence all the socialised benefits (healthcare etc) for elderly family and relatives through family reunion programs.
From the sponsoring business perspective you gain a valuable model employee who will do EXACTLY what they are told to do, for fear of rocking the board and no longer able to gain the carrot at the end.
However, there is an implicit tax extracted from the overseas visa holder for this juicy carrot, in the form of acceptance of lesser contracts.. That tax is captured by the sponsoring business, rather than the government via the lower wages. Further, it reduces upward pressure on contracts for exisiting citizens.
Yes, I'm sure there are reams and reams of useless paperwork, expert reports, studies, surveys all produced, most likely complete junk when held up to scrutiny to provide a fig leaf of plausibility for an outcome that was always desired by both the Airline and the Government. It's so much more convenient & personally profitable to buyback $1++ billion of shares than invest in your business through training people.