In the end, it turns out that the Coneheads can't even go back. They became so assimilated that their own kind considers them traitors and wants to kill them. Maybe it's not the same as deporting a 40-year-old mentally ill diabetic who's lived most of his life in Detroit back to Iraq (he died there two months later), but the uniforms sure do seem to match.
Planet Of The Apes (1968) Is About How Fake News Can Reshape Society
Today, nearly everyone agrees that fake news exists, and that it is bad. They just disagree over which side is actually using it, and therefore which side should go fuck themselves. Historians will probably spend a lot of time studying the way the factions in 2020 America didn't disagree on opinion, but on the nature of reality itself. They may want to start by watching Planet Of The Apes.
The villain is an orangutan named Dr. Zaius, who holds an impressive triple-title: member of the Ape National Assembly, Minister of Science, and Chief Defender of the Faith. He's therefore a politician, a scientist, and something of a pope. Zaius thus controls the flow of information on the ape planet, keeping stuff from the general population which he deems to be "dangerous" according to their Articles of Faith or Sacred Scrolls.
This includes scientific facts, like how flying machines are impossible. The chimps Zira and Cornelius are scientists, yet they don't question this propaganda until Heston shows them a paper airplane. They could have deduced the facts based on observable reality, but apes, like humans, don't work that way. They had been presented a worldview, and once it was accepted, facts were filtered according to whether or not they fit it. If your reply is, "That's right, the other side DOES do that! They're basically a cult," well, that's part of it. You spend all of your time dismissing other people's sacred truths, so you never scrutinize your own.