I have a friend on a property with cave art here in the hunter valley of Australia. We really don't do enough to preserve it at all. He's responsible and ensures no harm but it's still weird to own private land with 10k+ year old art and have no one really give a damn about it. Compare it to European attitudes, eg. Lascaux where they closed off the cave completely and only allow tourists near the modern reconstructio…
I think it's because of a sense of ownership and belonging (or lack thereof). People who made the art in Lascaux are, in a distant sense, ancestors of the present-day French. Most of Australia is of British ancestry, transplanted in the past few hundred years. The majority of them, including their government, obviously don't consider the Aboriginal heritage as their own.
If they really actually cared, they would have protected these sites.