Good points. Regarding how such people come to influence, you have to remember a lot of people, especially in startups, are not hired through a process at all.
I worked with a guy for many years who was as described in this article.
He can't code and he can't do any math, despite holding a phd. He can talk about math and he can talk about code, but we're talking excel level skills when what you need is someone with a modern ML level skillset.
He made all the decisions about which trading strategies were worth pursuing and which ones weren't, despite the presence of plenty of more qualified people.
How could this be? First of all, the boss of the fund did not have the skills to judge who could write a trading strategy, and who couldn't. So he was stuck with recommendations from other people who also didn't have this skill, leading to this hire. He also relied on his bias towards people of his own ethnic group, which benefitted this chap we're talking about greatly.
Essentially, broken feedback. Someone who can't judge relying on the judgement of someone who isn't competent but has his ear.
I'm sure this has happened to a lot of folks. Probably you need a somewhat larger organisation for there to be enough informed people to point fingers, and you need some luck for the culture to be such that a complaint would actually come through rather than be suppressed.