1. There are counties in England which have more distinctive linguistic features in their dialects than Australian English has from American English or UK standard English 2. A country like Indonesia to take our neighbour has cultures with more differences between them than we are from France or Germany, or even Turkey for that matter 3. You might as well say that because Tasmania has Errol Flynn, David Boone etc it has a distinctive culture too 4. The fact that some of our cultural icons are quite happy to move to the UK or US and fit in perfectly well there - Rolf Harris, Greg Norman, Rupert Murdoch indicates our 'culture' is really just a subculture of the anglo-celtic one 5. The fact that our TV shows and humour are easily understood in the UK Neighbours, Kath & Kim, Dame Edna and often become more popular there underlines that our culture is only subtlely different
The point is not to denigrate the Anglo-Celtic culture or the Anglo-Celtic Australian subculture - which is as good as any other - but just to point out that's it's not really unique as we like to think and barely more attuned to this land than any other.