Even still, weren’t their dozens of people shoveling gravel and only a couple of vice presidents? The pyramid structure of corporations imply that not everyone can go from the entry level work to the c suite. It’s an attrition and numbers game.
Plus, most companies now outsource their grunt work. The janitor cannot become the CEO anymore, because the janitor is a contracted worker, making minimum wage, not invited to the Christmas party, and prevented from speaking to anybody in a position of authority.