Right, but that they are ever visible to anyone means that the story could just as easily be inspired by the rarely-seen 7th sister, rather than the last-seen-100k-years-ago 7th sister.
There are plenty of fields where we entertain "mysteries" that have perfectly rational explanations but settling the question once and for all with a rational argument would dry up the funding stream for accademicians and could have other undesirable consequences on some countries' political narrative.
And then it a sense of incredulity is showing, it's unimaginable, 100,000 kya is unimaginable, as if the world was fashioned in the mesolithic.
Who, if I remember correctly, are estimated to have settled about 50kya. There are later intrusions into the peninsula, as it were back then. Oceania was settled even later by boat. The language divide in Australia is overwhelmingly that of earlier indians (if you'll excuse the pun, the land bridge was connected to the Indian subcontinent), with other language families mostly limited to the north end
This I think might strengthen the argument significantly.