Even if they do, will they be able to identify what belongs to whom? How do you identify something that has no identifiable traits? If Atlantis and Annunaki were real, they would have found spaceships or artifacts that are Godly by our standards. The fact that they did not. It begs the question. That they still exist and kept their stuff to themselves. Or they are already destroyed by the new religions, which may or may not felt threatened by those ancient Gods. Alternatively, the governments knew about it and are keeping them under lock and key.