Whenever I see an easter island head, I can't help but draw parallels between our global civilization and theirs. The eastern islanders consisted of around a dozen tribes, each competing for resources with others. It's thought that all of these statues were put up in a race by chieftains, competing with one another to put up the biggest, most refined and the best statue. I wouldn't be surprised if they competed in th…
Their first problem was that they and their palm trees were too big for the island. A big body size means a low population count, and that means that range of random fluctuations overlaps with zero: extinction. This is why island species evolve towards dwarfism: the Flores "hobbits", dwarf elephants, etc. Like many species that are seeded onto an island, they died out before they could evolve to meet the challenges.
The second problem is that humans are not built for a stable, hospitable situation. Our ability to adapt to change atrophies, so that an emergency becomes a catastrophe. (Look up "water empire".) We are built for constant warfare, plagues, droughts, floods, and so forth.
> I shudder to think what it must have been like to live in this world.
About like the sad story of Rhodesia, renamed Zimbabwe and destroyed as an exercise in social justice.
> Like the eastern islanders we have nowhere to go...
If we build big enough, soon enough, we get the inner solar system, whose resources make our current civilization look like a molecule of water in an ocean. Then we can take the gas giants as an afterthought, whose resources make the inner solar system look like a molecule of water in an ocean. Then we get the galaxy.