Australian Aborigines descend from modern Humans just as Europeans and Asians do. Genetically that is trivial to show. Also we interbreed easily. So there is no benefit for any use of the term "speciation".

Their "genotype and physiology" isn't that unique by the way. Genotypically there are tribes in Africa that diverge more from each other than Europeans diverge from Aborigines. People who think otherwise tend to overvalue skin color...

A lot of it probably comes down to politics and the terrible history of labeling groups of people as less than human. What is and is not a subspecies is already fairly vague and not necessarily of particularly high value (so you've labeled two individuals as different subspecies instead of the same species, so what?)

What use is the term "subspecies" with Humans? No beneficial use has been established, so we don't use it, end of discussion.

Yes, it case it wasn't clear, this is exactly my point.

Basically, this: https://en.wikipedia.org/wiki/Homo_floresiensis#/media/File:...

"Survived until the late Pleistocene" and "Have been separated since the late Pleistocene" are very different things.

Let's imagine if Australian Aborigines were in fact extinct and we found fossils, DNA, bones, etc. Would science have considered them a separate species?

It's an interesting thought, although it's not very meaningful to take further due to a variety of reasons.

You could ask this question about many human populations

What's so unique about it?