I've never worked for a truly large company, so maybe I lack perspective. But the idea that a company could incorrectly hire THOUSANDS of people over a few years boggles my small-company mind. Hiring is so exhausting, so time intensive and so boring. And it does nothing (directly) for the bottom line - instead it costs a ton of money! Given the ultra-mega-hyper-elaborate interview process at a lot of these companies, we're talking literal fortunes on top of fortunes worth of manpower (er, personpower?).
Imagine paying hundreds of people to hire thousands of other people and then saying "oops, we overshot by 6,000 hires!". How can any person in a leadership role that is responsible for that kind of misfire possibly keep their job?