Eliminate those that know the history.

I have acquaintances that live in what used to be South Vietnam. After the fall of Saigon, those older than 40 were moved out of the cities away from children and grandchildren.

This way it only took 1 generation to flip a culture.

And so they were made to wander for a generation in the wilderness until the entire older generation died off. This is a consistently used scheme. Invent a new way, destroy everyone that remembers the old one.

I understand, they "gave" all the under 40 jobs and took over the education of their children.

So programmed are they now, that the adults have a "required" nap after lunch