Hopefully Australia won't adopt the US system of income tax based on citizenship, with US passport holders being liable for tax on their earnings even if they haven't set foot on home soil for 20 years.
Unfortunately, the Aussie expat is a lucrative targeted for the ATO, as due to the distance and cost of commuting, Australians doing this need to be earning very good money to make it worthwhile. Some countries are a source of cheap labor and a lot of effort is involved in for example, going after thousands of construction labourers for a very small return from each one, whereas an Aussie working in Hong Kong or the Middle East and coming home regularly, would be on a very attractive package. Low hanging fruit for the ATO.