I don't understand what you're saying. Do you think I believe in a global flood, and you're citing Australian Aborigines as a counterexample?

While I did say that such stories occur all over the world, I did not say that every traditional people has such stories, without exception. Such a claim would support the idea that there was a global flood, and it would be impossible to prove without asking everyone through the history of the world. So I don't take such stories as proof of a global flood. I don't believe there was a global flood because that doesn't make sense.

Instead, this is how I understand it:

Many civilizations developed near large bodies of water. These people would have experienced significant flooding at the end of the Ice Age, which would have inspired tales of a global flood. That could explain why many traditional people worldwide have such stores, without needing to assume that the flood covered the mountains worldwide.

I would not be surprised if people native to high altitudes or continental deserts don't have flood stories because they would be far less likely than people living in coastal areas or river plains to have experienced widespread flooding. I'm not saying they all absolutely wouldn't, I'm just saying it's less likely.