Most of the time, the person isn't even a millionaire or billionaire when the company starts/grows -- but even at the very early stages, there is something different and slightly batshit about them.
And speaking from personal experience as someone who has also worked at high-profile startups (some very early stage), that's kind of part of the appeal. An audacious leader can be charismatic and compelling. And then once you're "in it" you start to normalize the increasingly batshit stuff you see, writing it off as "that's just X being X" -- which can often be unhealthy because with no accountability, things can go from "eccentric/audacious but ultimately helpful" to "this is insanity and is harming more than it is helping."