Most people would consider being the last person on earth to be the supreme torture. It would be a form of solitary confinement except the entire globe would be your cell.
Humans are social creatures, and we do best together whether we like it or not. When it comes right down to it, each other is all we really need.
Ask anyone that has had to abandon their home in a moments notice during an emergency or disaster.
Victims of natural disasters like wildfires have reported on what goes through their minds at the moment of reckoning.
Hint: it has nothing to do with stuff.
We don't need money - we need each other. We don't need to buy things - we need to share things. Yes, our stuff, but also our thoughts, our ideas, our dreams.
Working together while sharing our creativity has the power to create change and build a better world. A world that recognizes what is really important and what we really need.
Then maybe we can prevent there ever being a "last person on earth".