There are some wonderful SF stories about human settlements on other planets running wild, changing, sometimes becoming unrecognisable in the process.
Brian Aldiss’ “Enemies of the System,” for instance, left indelible tracks in my mind. It merges a remote human future with evolutionary radiation through deliberate scientific intervention and classic Darwinian adaptation to new worlds, bringing home the ephemeral nature of our existence.
Another Aldiss novel, “Non-stop”, deals with the theme of a culture running wild, a kind of “Lord of the Flies” in space if you wish. It ends with the protagonist discovering that they find themselves in a multigenerational starship, necessitating an escape from barbarism.
My own short story, “Beyond the Wild Mountains” (Abyss & Apex, 2013), deals with a settlement on a new world that had similarly fallen back onto primordial cultural forms. Steeped in ignorance, the protagonist clashes up against technologically advanced “aliens” with devastating consequences.
Wherefore our interest in stories like these? In essence they draw from our past to imagine possible futures and ponder on what it means to be human. Often such stories reflect existential fears about our own civilisation; fears about how thin the veneer of sophistication between ourselves and primordial anarchism really is.
Ever in the background of our minds lurks a collective memory of the decay and fall of Roman civilisation, the plundering of the eternal city by the barbarians. It reminds us that what we have wrought and built up with so much effort over the centuries, can easily unravel and fall apart. In fact, it seems inevitable that this would happen.
Thus, SF is not really about the future. It is very much about the present, and about how we imagine our past. SF often reflects our thinking about society, culture and civilisation, and our fears about what might happen to us; and it does so whether the author wills this or not.