Expected value and risk-seeking leaders
It’s easy to see how an evolutionarily stable subset of humanity could arise that compulsively takes insane risks to gain leadership positions.
Various primates, including humans, tend toward social hierarchy, with a greater or lesser tendency for there to exist a single male leader that may greatly, sometimes wildly out-reproduce the rest. For example, the current state of genome evidence suggests that 8% of all Asians are descended from a single male less than 2,000 years ago, presumed to be Genghis Khan.
Evolutionarily, that kind of payoff is worth some risk. A lot of risk, in fact. Even an action with an 90% chance of sudden death (”hey guys, watch this!”) is “worthwhile” if the increase in reproductive success is sufficiently vast. If the expected return is positive, evolution will make that risk-taking tendency increasingly common in a population, until the odds renormalize.
As a result, it is easy to see how something we today call a pathology — compulsive risk-seeking behavior, as occurs among gamblers, short-term traders, Kennedies, and would-be teapot dictators — is evolutionarily possible.