After standardizing Newspeak and totally crushing resistance, life floats on for unknown thousands of years. Until aliens arrive. Nobody knows what to make of them at first; interpretations of what is happening ripple through society but keep getting revised.
The view that belief & control of information can control reality just keeps getting its ass kicked by the aliens & their genuinely better technology, weapons, & organization systems. They're just one step ahead, blowing up the party members. Even when they wipe out all inner party members, the outer party members just keep doing the same old thing.
Eventually the kind-hearted aliens figure out what happened and try to teach people some logic, and the true meaning of history. But it doesn't take.
In memory of Earth's past and the promise it once held (which they dug up and mourned), the aliens decide there's only one thing to do - they scrub the face of the earth of all humans & their relics, and set up a few camps of only babies, selected for diversity and with a few selected genetic modifications predisposing them to rationality, and a deeply hatred for authority, and plop them down in the forest with robots set up to feed them for a few generations until they figure out how to hunt.