My summary of his book is that people rise to power by contributing to the greater good

Like owning an Emerald mine? And be surrounded by influential people who help you, because you’re filthy rich?

The paradox is that it’s been suggested by several studies that those that gain power (or those that feel powerful) tend to be less empathetic and focus more on themselves.

That’s not a paradox, it’s easier to get rich risking other peoples money if you don’t give a shit about them in the first place.