They do at a state level, but given aboriginal sites aren't buildings protected by codes and standards - they're gigantic bits of land with scattered artfacts like stone tools, or trees with markings, or remnants of old sites.. There's nothing really left.
Think about it like this, if you were in Ireland, there might be a small hill and that was remnants of a hut. If you excavated it, you might find some stone from the walls.
But these sites are on a land mass where time doesn't bury sediment over the top of them very much, so what happens is whatever is left usually just wears away by the harsh environment.
People want to protect these sites, but none of these sites will have any visitors for years, decades in some cases. This includes people who live in the state.
To be fair, there's plenty of work that could be done preserving what's there and excavating underneath - or land moving the top few meters.. And we could make companies do that. But that will just drive organisations and land owners to hide these sites exist in the first place.
Or just move to another remote area to do the same for less profit. But good luck hurting profit in Australia. That's not a political game you've got a chance of winning during our life time in this country.
Always was, always will be..