Perhaps our own statefullness is a hack of nature. We have electrical signals in our brains, neurotransmitters, neuron growth. By any reasonable measure it’s a hack on top of a hack. But it works well enough for us to get buy. So it does for the agents.
That is true that intelligence is kind of a "freak of nature" in a way, but it's also true that even single neurons are extremely efficient, and the brain has a lot of recurrence that isn't represented at all really in today's artificial neural networks.
