Pandemic highlights ridiculous inconsistency

Over the past few months I have been planning a getaway to Queensland, as I expect many other Peninsula people have been doing.
With border closures, it is a nightmare to determine where, how and when borders can be crossed.
There is absolutely no consistency with any decisions made by individual states in this one country. Queensland has decided only people from parts of northern NSW can enter their state.
However other areas of NSW have had no cases of coronavirus recorded and are on the banned list.
At the same time, all of NSW is now allowed into ACT and SA with some minor restrictions.
Changing my plans to include the Northern Territory, I discovered after talking to their tourism department it allows people from Gosford to enter with the restriction that they have not travelled further south than the Mooney Mooney bridge or travelled through Victoria.
She did ask why every place had to be said twice: Mooney Mooney and Woy Woy.
Why the difference between these states?
Why can’t the Prime Minister of Australia make decisions effecting Australia regarding border closures?
Why is there not a consistent definition of hot spots?
Why is there not a consistent definition of who can cross any border as SA, NT and QLD have implemented different regulations effecting the same cohort of NSW residents?
My biggest question is “Why do we need three layers of government?”
Get rid of the state governments and get consistency in Australia for taxes, health, roads, rail (rail gauges are still not the same in all states), education (same qualifications), policing, infrastructure e.g. dams, water resources, rural land use, national parks, fisheries, and to some extent public housing.
The savings in wages by not doubling or tripling government departments, having different stationery, office rents, office buildings, transport and travelling would save the country billions.
I know this has been mooted before.
The current pandemic has highlighted the ridiculously-different application of regulations.

Email, 25 Sep 2020
Jim Brooks, Woy Woy