It’s an act of hubris and idiocy to think that people in the last ice age were somehow stupider or different in their wanderlust than people today. Today people build boats and navigate over the horizon in search of adventure. You can’t assume that, in 1,500 human generations that never happened. Of COURSE it happened ....many many times.
Exactly. There’s no land bridge from Southeast Asia to Australia, but the Aborigines arrived there some 50,000 years ago.
Due to the Ice Age the sea level of that time was up to 300 feet lower, making what is now Malaysia, Sumatra, and Borneo a vast peninsula, but even so, there were over the horizon water gaps that meant people made boats and went out to sea beyond any land the could see.
Similarly, people used boats to go up along the coast from Japan all the way to the Aleutians, which were much bigger because of the lowered sea level, and from there on to Alaska, the coast of Canada and eventually the rest of the Americas.
It would be a good life. Camps on the beach, plenty of seals and fish to hunt and eat, and adventure galore. They wouldn’t have to go the whole distance, either. Only a couple of ten miles per lifetime... It would only take 2000 or so years to go from the Aleutians to Tierra del Fuego.