Warning: The following contains SPOILERS for Don't Look Up.
Adam McKay's satirical comedy Don't Look Up features a number of unsavory characters, one of them being White House Chief of Staff Jason Orlean, played by Jonah Hill. At the end of the film, Orlean is inside a NASA control building with The President and the CEO of tech company BASH, where they are monitoring the launch of drones that are meant to take out Don't Look Up's world-ending comet with explosives. Of course, this plan goes awry and the NASA staff all abandon the building, (as well as The President and BASH CEO), leaving Orlean all alone, who is frozen in fear. After the comet hits, essentially wiping out all life on Earth, it's revealed that Orlean survived, climbing out of the rubble of the NASA building, announcing himself as the "last man on Earth," which is highly unlikely.
The son of President Orlean (Meryl Streep), Jason Orlean is a rich, privileged, self-centered, egotistical moron, who is willfully ignorant not only of politics, but of how the world works in general. The Don't Look Up character is essentially acting as his mother's lapdog throughout the film (even carrying her purse for her). The irony is that he is shamelessly attached to her, but at the zero hour, his mother makes her escape from Earth in a life-sustaining vessel with the BASH CEO, never giving her son a second thought until it's far too late. Jason is ultimately saved by his own fear, as well as his lack of any real friendships or relationships, as being stuck inside the NASA building (which everyone else evacuated before impact) is what kept him alive.
In the post-credits scene from Don't Look Up, Jason is seen amidst the rubble and begins screaming for his mom, just before making a quick video on social media. In the distance, it's shown that the world is in shambles. While the scene is meant to be a joke and played for laughs, it's entirely possible that Jason could've survived the initial hit, given that he was in a NASA building that potentially had a better structural foundation than most. As to whether or not he's the "last man on Earth," that's highly unlikely, given that there are hundreds of thousands of structurally sound buildings around the world that could potentially keep people safe in the event of a comet impact, let alone underground bunkers, etc. that are already built or would be built by the government in anticipation of such an event (although that's never shown in the film). With organizations, governments (like Don't Look Up's Planetary Defense Coordination Office), etc. already planning and preparing for catastrophic events like this, it's beyond likely that Jason would be joined by a much-reduced population, but he would not be the final bastion of humanity.
The bigger problem Orlean would face after emerging from the rubble is basic survival, as he would find himself without the creature comforts he's so accustomed to and fond of. Don't Look Up doesn't venture into portraying the realistic after-effects of a comet strike — as Orlean would now face nuclear winter and a cavalcade of after-effects that would affect what's left of life on Earth for a very long time. That doesn't mean he couldn't survive past his initial reemergence from the rubble, but it would take finding some resourceful survivors much smarter and stronger than him to make it happen.
The choice of having Orlean survive is an even more interesting query. McKay chose to keep him alive after the asteroid strike, so the question becomes, "why him?" The answer, most likely, is irony. Of all the people from the divisive Don't Look Up who could (or should) survive the impact, the most selfish, egotistical idiot is the one to do so. The scientists and activists who attempted to save Earth in the film are dead, with the remaining worst of the worst having fled in a spacecraft to look for a new place to live. Having Orlean be the "last man on Earth" is a cynical commentary that fits the film's overall narrative, which forsakes humanity with the worst it has to offer.
