Now imagine those people being recruiters, bosses and other gate keepers with considerable power over careers. It's dangerous to be a humble introvert in a world that's anything but.
But as a recruiter or boss, the onus is on me to suss out the data I need. Given that introverted people have always existed and will always exist, it would be ignorant and lazy of me to only pick from the crop that puts themselves in the spotlight for me. Not to mention the very obvious fact that a lot of people are very good at selling themselves, even when they have nothing to offer.