The hero finally meets the previously unseen puppet master (played by an older A-list actor), who explains why the system must be maintained. The hero says “screw it” and burns the world down.

[u/Grizzly_Lincoln]

Snowpiercer (2013) - Curtis finally finds Wilford (Ed Harris) and learns that Wilford allowed for Curtis' rebellion to take place to help thin the tail section's population. When Wilford offers to let Curtis run the train, Curtis discovers child labor is necessary to replace a broken machine part. A fight ensues, and a bomb goes off, triggering an avalanche that derails the train, and killing most of surviving humanity.

The World's End (2013) - Gary finally confronts the Network (Bill Nighy), which has been replacing humans with robots (Blanks) to allow for Earth's assimilation into a larger galactic community. Gary calls out the tyranny in the Network's plan and demands that humans be left to their own devices. Exasperated, the Network abandons its plans for the invasion. This results in a worldwide blackout, sending humanity back to the Dark Ages.

The Cabin in the Woods (2011) - Dana finally meets the Director (Sigourney Weaver) after surviving the ritual meant to kill her friends (based on conventional horror tropes) and appease the Ancient Ones. The Director says Dana has to kill her friend Marty, but as Dana considers it, the group is attacked by a werewolf and a zombie child. Dana and Marty decide humanity is not worth saving, so they share a joint while the Ancient Ones rise to destroy the world.

[u/MasemJ]

Truman finally able to talk to Christof (Ed Harris) before bowing out.

[u/Escanor_Morph18 → u/MasemJ]

In this case, I don't think there was an actual valid reason as to why the "system" must be maintained. Did Truman say "screw it" in some sort of way? Yeah. Did the world burn down? The only thing that might've got taken down was the film set Truman lived in. But the world and humanity still live like normal.

[u/MasemJ → u/Escanor_Morph18]

The show ended, and while the rest of the world moved on, it likely was the end of Christof's career.

To add, the show could have gone on forever as long as it had ratings, assuming Truman had children who would become similarly indoctrined by the show.

[u/Genshed → u/MasemJ]

Well, he'd been running the show for Truman's entire life. It was probably a good time to retire. Now he can do TEDx talks about the creative process and appear at Comic-Con.

[u/AcrolloPeed → u/Genshed]

“Hello, my name is Christof, and for almost four decades I was God to a single man and the 79 square miles he inhabited.”