As long as the route was open, small groups of humans would continue to migrate wherever they found new resources to survive. It's easier to believe family or clan groups migrating, each choosing its own pathway, than a focused mass migration.

I'm always suspicious of maps showing big arrows pointing in one certain direction. They should be as complex as a turbulent stream, with eddies and backwaters swirling backwards and forwards, splitting and rejoining, speeding up and slowing down chaotically.

Consider modern America -- what was "The Way West" ? It was multiple trails, traveled at different times by different groups, spread out over decades. Why think early humans, with fewer technological aids, less knowledge of their destinations, and forced to feed and supply themselves on the march, would travel in larger groups on an organized schedule ?

This is evidence that at least one group passed that way. In no way does it rule out the possibility of other groups, maybe even most others, taking different routes at different times.

15 AUG 2024

A new archaeological study led by the University of Oxford in collaboration with Universitas Gadjah Mada has identified the oldest plant artefact made by our species outside of Africa in a cave in West Papua. This suggests that the earliest Pacific seafarers arrived in West Papua over 55,000–50,000 years ago, introducing to the region complex plant processing and maritime skills. The findings have been published this week in the journal Antiquity.

‘Charting the earliest dispersals of people into West Papua is vital because it lies at the gateway to the Pacific, and helps us understand where the ancestors of the wider region — including Australia, Aotearoa/New Zealand, and Hawai‘i — came from and how they adapted to living in this new and unfamiliar sea of islands’ said lead author Dr Dylan Gaffney of the University of Oxford’s School of Archaeology.

Despite the Pacific’s critical importance for global population movements, scientists have not yet been able to pin down exactly when and where early humans travelled on their journey into the region. At this time, the Earth was in an Ice Age, meaning that sea levels were lower: the large continental shelves around Asia (called Sunda) and Australia (called Sahul) were exposed as dry land, but many of the islands of Southeast Asia remained islands.

Our species — Homo sapiens — may have moved along a “northern route” from what is now Borneo into Sulawesi, Maluku, and then West Papua, or a “southern route” from present-day Java and Bali to Flores, Timor, and then Australia (see map below). Previous research has hinted that seafarers arrived to Sahul perhaps as early as 65,000 years ago, while other archaeologists insist that these maritime crossings did not take place until after 50,000 years ago.

More:
https://www.ox.ac.uk/news/2024-08-15-oldest-plant-artefact-found-outside-africa-reveals-pacifics-role-early-human