Markey-Towler's thesis is that federations perform better than unitary states, and that Australia has been drifting away from an ideal federal system. That all changed with COVID, and for a brief period we saw the states behaving as separate entities.
His monograph brilliantly dissects what the states did and how differing state practices produced practical winners that can be followed next time.
Federation was almost back to the days when the states levied their own customs and excise with travel between states strictly controlled, and the High Court endorsing this action.
The opportunity to observe differentiated policies implemented so quickly, and with tangible and measurable outcomes will hopefully not happen again in our lifetimes, as it has never happened before in anyone's lifetime.