Why do so many men in power men appear so inadequate?

Who is a parvenu?

Dictionaries agree to define it as a person who has acquired a superior economic and social status without adapting to the manners of the new context.

In most countries the man in power, who inevitably aspires to charismatic leadership, is too often a parvenu.

We can define him as

a person who has gained a power position without adapting his preparation to the one that the context requires.

In short, parvenus of competence, which Honoré de Balzac well describes with this brief thought:

Parvenus are like monkeys, of which they have the agility: […] during the climb one admires their agility, but once they have reached the top one can only see the shameful parts of them.

What do you think?