The other advantages places like NY LA and London have over little old BN SY and ML is, they have been very busy for a very long time. They have extremely well developed processes procedures, and airspace designed for moving aircraft.
In Australia traffic in some regions has exploded. In places like BNE you have only two approach controllers trying to force an extra 40,000 movements per year through airspace that was designed before anyone wanted to go west. There is no other airport in the world moving 220,000 aircraft per year, almost totally onto one runway, with only two approach control positions. It's all happened so fast everyone has been caught off guard, ASA with staff and airspace design, and BNE with infrastructure. But the new runways on the way (slowly), the airspace is being redesigned as we speak, and come November a new departures position opens.
This is only an example of the big picture in Australia, controllers working too much overtime on combined sectors with too many aeroplanes per person. I don't know if this was a factor in the Adelaide incident I guess it'll all come out in the wash.