I think the main difference is the scale of the display being used by the radar controllers. In the US, they have many more sectors, generally with a display area less than 100nm. Compare this with the screens that are used here where a controller may have from North of Cairns to South of Rockhampton on the display.
Approach work needs a small range and a controller that can concentrate on this, not someone covering such a wide area and fielding flightwatch duties as well.
It's the same answer to the other items floated by Dick recently, all it takes is controllers and money. We don't have the controllers
. Talk to the Minister about the money.