I think the theory is that capitalism pits the unbearable assholes' psychotic ambitions against one another and allows the normal people to reap the benefits of their relentless competition, while a functional democracy regulates the economy to prevent any one particular asshole from gaining too much power and enforces regulations to handle the externalities, and that in a functional democracy nobody who is too much of an asshole can ever get too powerful.

Of course, all of that presumes a functional democracy and... well... [gestures around broadly]