I don't think having it in your constitution would have necessarily prevented this mess. Even in the US we get old farts applying creative interpretations to our constitution that suit their desires, or even occasionally violating it because they know how many years it will take before the justice system can correct a violation.

Like all written law, it's not written to protect the citizenry, it's written to protect the elites. Just, in the case of liberty, it's that not agreeing to back off and give us some freedom means we will perform very naughty actions that I may not legally describe on clearnet. The nature of liberty is steeped in violence, and aussie elites might get a unique chance to learn this if the citizenry discards the notion that it must be gifted from above. In other words: granting liberty in a formal document primarily serves as a boundary for politicians so they don't end up being violently overthrown by organic responses to tyranny.