It would be nice to not have to pay $50+ to get something to delivered to Australia.
$1000AUD is the de minimis threshold, for both GST and Duties.
Depending on the good, there would be duties as well as GST applied.
(I'm a wannabe trade nerd)
It's so bad that "Reshippers" are increadibly popular here (in Australia). They have a US address so you can ship Amazon stuff there, and then either do a bulk shipment of multiple orders to Australia, or else just accept their shipping charges (which are usually 50% of what Amazon charges).