SPOILER ALERT: The following article contains spoilers for the movie Downsizing. If you have not yet seen the film, and don't wish to know details about the ending, please bookmark this page and save it until after your screening!
The first act of Alexander Payne's Downsizing is pretty straight forward -- serving to not only establish the history of the science behind the titular process, but also explain how it wound up changing the world. If the director had his druthers, however, it would have had a very different opening that would have been set 5000 years in the future. Discussing scenes that didn't make the cut, Payne recently told me in an interview,
There were a few scenes, and a framing device - that all of this is being told like a myth from tiny people 5000 years in the future. The big extinction did come, wiped everyone out, and then we pick up the story with the tiny people who have repopulated the planet coming out of the vault 5000 years in the future. And an old storyteller is telling children around a campfire, 'Years ago, the world was ruled by giants.' 'Ohhh!' 'But the giants were always hungry, and they fished all the seas, and killed all the animals, and burned down all the forests, and made the world unbearably hot!' 'Ohhh!' And then he starts to tell the story of Paul Safranek.
Last month, I had the great pleasure of sitting down with Alexander Payne for an interview during the Los Angeles press day for Downsizing, and it was while talking about the edit of the movie that he brought up the deleted framing device that didn't make it into the theatrical cut. Recognizing that the film has a sizable runtime of two hours and 15 minutes, I inquired how much material hit the cutting room floor. He then explained how the movie was originally designed to open completely differently, following characters who come out of the aftermath of the film's ending.
In the third act of Downsizing, Paul Safranek (Matt Damon) finds himself on a special trip to Norway, where he learns about a special doomsday plan that has been devised by associates of the scientist who invented the shrinking procedure in the first place. They have constructed what is basically a massive underground biosphere that will allow generations to live on even after the planet died. As described by Alexander Payne, the framing device would have followed the ancestors of these people, who had heard stories passed down about a strange man and his choices in the time of Downsizing.
As for why this opening wasn't included in the film, the answer is exactly the one that you would expect. The movie is already pretty hefty in the runtime department, and Alexander Payne felt that it needed to get the axe:
The film was running long. I miss it, and I like it. We still might use it in the future. But the picture was running a little long, and that's the basic answer.