Sorry I don’t follow. I think we agree that if nobody survives or people are forced to exist in a hostile culture it’s harder for them to propagate their stories.
But if we go too far we ignore the work of the brilliant people who did manage to preserve their account of events. From Indian perspectives on Indian war of independence vs Sepoy Uprising, to native Americans, Aboriginal Australians, Maori people and so on fighting generational struggles to preserve their recounting of events and be acknowledged.