Apart from market size which IMO is irrelevant when the item(s) is being massed produced out of the same factory and shipped from the same country to both markets
ASUS T300/TF201 in Aust $900 in the US $400
A subscription to Wired in Aust $70 US $15
A Barska 15x40-50 spotting scope US $30 Aust $150
The list goes on and on, and this is why I refuse to buy certain items, I'd rather go without
a Julius Sumner Miller used to say
"why is it so"