That's the point of 'cultural isolation' that I am making.
The Anglo-Saxons wiped out the original 'indigenous' Britons at 99% success rate. The motivation to build 'Boats' came to being able to see the distant Briton coastline and its just a short trip across the Channel.
The Aboriginals 'walked' across into Australia and even when the water's rose, the tribes (Carpentarian) around the north still used small water-craft.
The Anglo-Saxons had the 'stimulation', first in regards to who they wiped out and then with influx from Danish (Scandinavians) from the north, more Germanics and even small pockets of Gauls. Half of the Irish came from 'via Spain/Portugal' (Iberia) and before that : Cathage, Lebanon and down from the Balkans. Throw in the Romans who were already well stimulated 'culturally' and you can see how the Anglo-Saxons (West Germans?
) learned more than what they originally had. Even still, at the time of the first Roman 'habituation' (Invasion came later) - the Anglo-Saxons were nothing more than a primitive 'forest' people with Druidic 'naturalism/animism' beliefs. Stonehenge and Barrows were as good as it got.
Being 'Nomadic' had its cultural advantages - they got to visit many other cultures and share ideas, but the Aboriginals got cut off and forgotten. A sanctuary from the world's problems or a Prison for 40,000 lifetimes?
Its kinda sad seeing people who are totally dependent upon 'City' living and couldn't cope with life on the 'outside' - institutionalised.