That's not the way I understand it. The difference is other countries have laws for average CO2 emissions of their fleet, so they need vehicles that are low emissions in their line up that need to sell to bring the average down. Australia doesn't have that so manufactures have no desire to ship those cars here - instead they get sold in countries where they need to and we just get the rest of the range. Imagine how Toyota and ford would cope with fleet targets - they would struggle as the bulk of their sales are all higher emission 4wds
https://www.eea.europa.eu/ims/co2-performance-of-new-passenger
New Ranger - 192-204g/km CO2
300 series - 235g/km Co2
Hilux - 207g/km Co2
Prado 209g/km Co2
EU fleet wide target 130g/km CO2
Actually that is the way I see it as well, but not as a "dumping ground" for high emission vehicles, but the manufactures selecting vehicles that the Australian public want to buy that just happen to be higher emissions vehicles than they sell into countries of smaller land mass/more urban environments.
As you suggest the vehicles you have listed are generally available in other markets, not just dumped into Australia out of some special high emission factory, but they aren't big sellers in Europe, or Japan because the market is different.
I foresee the requirement for manufactures bring their average emissions down will mean heavily discounted (loss makers?) low emission "shopping trollies", and the higher emission vehicles becoming more expensive to maintian net profits.
Not necessarily a bad thing, but my brain then askes the question - all these high efficiency buzz boxes are generally in their best environment commuting in the urban environmment, so therefore why not be even more efficient and just use public transport?