Shortsighted and Eurocentric, where were you educated? The internet? The Aboriginal nomads were the first to discover North America around the time of the last ice age. Exact date and migratory waves is debated, but population movements and territorial discovery is consistent with the Archaeological data. I have included some supplementary reading I think you would benefit greatly from.
I thought discovery was the legal tool for finding facts, as far as original man is concerned, the oldest human remains: it was in Ethiopia, and it was called ‘Handy Man’ , translated from Aramaic, incidentally, the language of Jesus.
All other aborigines were transplants.
Ancient Aramaic has very old middle eastern-African roots.
They gradually disappears because
1.at that time maritime transportation over ocean is not easy, it is impossible to send a large group of colonists across acean easily and safely as the Spanish did later.
at time time, commerce is not that well developed, sending people across ocean to mine gold and silver and then sell those mined gold and silver back to the old world will not cover the costs and risks of maritime transportation, it does not make sense in bussiness.