the big thing here is the struggle between companies like amazon google apple who have tons of applicants, and a startup who has less applicants, and less experience from hiring false positives and identifying false negatives. They acknowledge that they turn down many good people, but also most if not all of the people not qualified. They arent worried about false negatives, they are worried about false positives. So they are willing to filter out a good portion of qualified people they aren't quite sure about who might have some overlapping results as people who are not qualified, knowing they are filtering out most if not all unqualified people.

Startups do not have the same level of people experiences to draw conclusions based on interviewing thousands and thousands of applicants and tracking the success of accepted applicants based on a large portfolio of information.

Probably the best thing you can do in a situation like this is GET someone from a company like that who has had years of experience interviewing candidates, and they will be able to bring along that experience of identifying potential false positives from the get go. That is honestly the biggest asset to these companies, their ability to hire and maintain high quality people.

in addition to the countless benefits and opportunities for varied career trajectories in multiple and evolving technologies for smart people once getting into these places, is the fact that they highly value the social network of these work places, and they cannot be duplicated in many places elsewhere, further incentivizing them to stay and internally recommending other high quality friends from elsewhere to interview.