OK, let's consider the opposite proposition: Most positions of power are occupied by people who are crazy, resentful, and irresponsible. It might sound cynically plausible.

That just sounds stupid to me. Being crazy and irresponsible are deleterious traits in those seeking power. Resentfulness is both something that the losers in the power game are more likely to feel and dwelling in resentfulness is something of a failure mode when it comes to practical power gaining. Don't get mad, don't get even, just take your next step to power.

The idea of smooth sociopaths who lie their way to power and riches via superior awareness of human gullibility is way overrated. In most cases, power is a reward for boring hard work, taking responsibility, and being effective.

These things complement each other. You need both if you are going to reach the higher echelons.

Unless you're born to power, you only get to have it and to hold onto it by working with some group of people who have a complementary power of their own, the power to depose you - your investors, your voters, your professional colleagues.

And here is where I rest my idealism and my optimism. I don't try to force people - particularly powerful people - to be benevolent and responsible (for anything but their own success). I don't force myself to believe that people are bastions of goodwill and paternal grace. I prefer to see systems and institutions set up such that plain old self interested hypocritical Machiavellian monkeys have payoff structures that ensure that their behavior benefits everyone else anyway. Any fundamental, non hypocritical and internally coherent goodwill beyond that is just a bonus.