The visiting boss of Universities UK, their Universities Australia equivalent, says that Australian students are used to studying near their home. It means student choice here will take longer to evolve than in the UK, where leaving home to study is common (they are getting a very partial demand-driven system).
That Australian students are stay-at-homes is a commonly held view, but there is not much research on how often Australians move to study. The DEEWR student statistics show that about 11% of students are enrolled outside their home state. But the 2006 census showed that about 40% of 18-19 year old university students were not living with their parents.
Of course many of these are likely to still be fairly close to the family home; living in a share house in Fitzroy is more fun than living with your parents in Camberwell. But it shows a capacity and willingness to move.
There are signs of national marketing. Both Bond and James Cook universities have been advertising on Melbourne TV in the last few weeks (admittedly SBS). This suggests that at least some universities think that students can be persuaded to travel long distances.
All the other mobility statistics – jobs, houses, travel – suggest that Australians are happy to go somewhere new or do something new. If student mobility to study is lower than in other countries I doubt it is anything deep in the culture. It is a pragmatic decision that Australian universities are quite similar, and that therefore there is not much point in moving to study. If universities differentiate themselves more, I would expect more mobility.