That and a whole lot more.
You've got a few different dynamics going on
Firstly, we've got a nice little cognitive bias that causes people to perceive individuals who make firm, confident statements as more competent than they are (i.e. most pundits and politicians). Meanwhile being reasonable, thoughtful, changing your opinions, and saying 'I don't know' tend to come across as less so. Corporate leadership is generally political and individuals with pathologies that lean heavily in that direction can tragically 'bubble to the top', and since people in upper stratas choose who gets elevated to higher levels it tends to feed itself.
And there's plenty behind the 'Power Corrupts' maxim. A lot of those individuals would be more bearable in positions without power, the power just causes them to relax the ethical boundaries that were holding them in check.
But there's something more tragic going on, because there also are a large number of CEOs and other individuals in power who were once extremely competent but lose touch with those skills as they advance in power. I'd have to dig up the research, I remember it being called the 'Paradox of Power' by some but that's probably not great from the standpoint of keywords.
And then on top of all of that there's the addiction aspect. There are individuals who are more prone to becoming addicted to the feeling of power and they're both the most likely to strive for it AND the least qualified to wield it when you have it. It's a dopamine addiction.
Basically people are complicated and it's a big ol' messy LARP where those annoying drama-queen power gamers have all of the advantages, the board never resets, and there's no other game in town so everybody's forced to play this crappy one over and over again.
There are still some really good people who end up on top of large corporations, don't get me wrong. . . in fact they're generally downright awesome in other ways because they don't have the flaws that provide them with all the inherent advantages. . .but they're tragically not the majority.
You can still hate the players who win by being awful people . . . but the real problem is the game.