Gigabit is _massive_ overkill, that's the real dirty secret here. That plan was a colossal waste of Australia's resources.
I had Gigabit network access twenty years ago (because I was a student). I could buy it today where I live now, I have plenty of money but I use 40/10 vDSL instead. Because it's fine, that's what having Gigabit all those years ago made apparent to me.
The UK has a horde of people who were absolutely 100% certain that Gigabit speeds will magically unlock... something. And they became available. And nobody cared, because it makes no difference.
Bigger numbers aren't better if the numbers you have are already perfectly fine.
8bit PCM at 11kHz sucks. 16bit PCM at 48kHz is fine. 24bit PCM at 96kHz is... not any better.
56-bit DES encryption sucks. 128-bit AES is fine. 256-bit AES is... not any better (yes it may be faster in some cases, it's complicated, but straightforwardly it isn't better)
The biggest problem in people's home networks tends to be Buffer Bloat, which isn't fixed by Gigabit except that it'll maybe make the vast buffers a bit more expensive and so the vendor will only put far too big a buffer, not far, far, far too big a buffer in your device.