Everything in life is a learning lesson.
So to create the illusion they simply needed their BIG LIE to last for 3 generations.
You needed to control the influence of The People.
Did you not learn from your mistakes?
Maybe, that was also part of the lesson.
Look at that as a WIN!
Each Generation has it's own problems.
Humans are straight up problem solvers that build huge tools in order to adapt.
Under ground or space?