The ancestrals for many years after their initail landing on Eden used their technology till they learned how to live without it. A few of the ancestrals were recluctant to give it up however and hid it so non would known they had failed to destroy thier technologies. After many years these ancestrals forgot about thier hidden technology and learned to live without it. This technology is still there according to some legends. The Relic beings are visible proof that this technology once exsisted and may still exsist.
Recent info revealed about this legend: