I'm not sure that the "iron ring" is where we all think it is - apparently there is a select group right at the top of aviation in Australia that meets regularly.
I'm told it comprises the head of the Department (DIRD?), the head of CASA, Airservices, the RAAF and perhaps others (ATSB?). They agree on policy and then direct the policy of their various organisations to make sure it happens. Given their positions, maintenance of the status quo (change is very dangerous and unpredictable - you've all seen Yes Minister!) would be high on the agenda.
The Minister would only want change if something was going wrong, and Australia's accident figures will be evidence that nothing is going wrong. Review committees (Forsyth) are the perfect vehicle for convincing everyone that the Government is doing something. Inevitably they all start their reports with "Australia is the safest place in the World to fly" before recommending lots of administrative, consultative and chair shuffling changes such as those happening to CASA and Airservices.
Perhaps the iron ring is right at the top and those we think are the iron ring are simply obeying orders? After all that is how most organisations work.....