Another way to look at this is that the crazy optimists who are the worst estimators never return (themselves eaten by predators, run out of water, hypothermia)

Another way to look at this is that the crazy optimists who are the worst estimators never return (themselves eaten by predators, run out of water, hypothermia) or return empty handed, lowering their reproductive success. The optimists who succeed quickly adjust their understanding of the estimating process ("Zog died when he went after deer at night during winter, and I barely survived being attacked by wolves when the deer were most plentiful, so I should go on cool midday hunts when the deer are already slightly down in population").