Of course they get many times more applicants than they hire. They have 1,200 employees but over 20,000 job postings on LinkedIn. I'm more curious about whether the people they end up hiring are their top choices. Because people need money for things like food and housing, it seems to me like forcing applicants to go through a months-long gauntlet with lengthy written essays, IQ tests, and 8+ interview rounds will filter out most people who are able to get hired anywhere else.

Process like that filters the best candidates because they are not that desperate. They can easily get job from healthier company.