Basically : In the ancestral environment, future gains were THAT unsure.
BTW, I would not be surprised if evolution led to populations enduring bad seasons to become better at planning, especially long-term, and if this played a role in the enlightenment and industrial revolution.
I asked earlier:
There are actually many attempts to answer this question in the economics literature. I’m not sure why I didn’t find them earlier.
One paper is Uncertainty and Hyperbolic Discounting and others can be found by searching for papers that cite it.
Basically : In the ancestral environment, future gains were THAT unsure.
BTW, I would not be surprised if evolution led to populations enduring bad seasons to become better at planning, especially long-term, and if this played a role in the enlightenment and industrial revolution.
Edit : Cold climates demand more intertemporal self-control than warm climates