The short answer to your post is that the Act can be amended, and the Act is in serious need of amendment.
I don't disagree. In fact not only the Act but every regulation and order made under the Act. But, I don't see any political will to bring that about while the general public is completely disinterested and the politicians don't want to be involved. Aviation is not a vote winner.
Can they become interested? Perhaps, but you will also have to interest a party to want to reform aviation in Australia because, as aroa said:
The political disinterest in Aviation has been going on for DECADES, and thru Governments many and various.
You have to convince the public that they are in serious danger and that is going to be a tall order. It would be a different matter if the FAA was to say something along the lines of "....you have failed our audit. Your aircraft are not allowed in our airspace. Our airlines are not permitted to be in any alliance with your airlines." I understand it came very close but politics prevailed.
Lobby groups in the US are very effective in the main because they are well supported by the interests they represent. In the case of the NRA it also helps to representing a very large percentage of the American public but even groups like the AOPA (US) and NBAA are effective because they are supported. Unlike Australia where our "rugged individualism" leads us to constantly complain about any group that tries to represent us. Look at the history of these groups, riddled with factional disputes and splits that makes the ALP look like a kindergarten class.