The recruiting funnel isn't supposed to be perfect. In fact, most of these 'elite firms' know that their recruiting funnels bring in, essentially, statistical noise. And that's just fine.

Your chances for being hired at an elite firm are roughly .5-1%, or roughly 1 hire per 100-200 applications. No filtering system in the world could accurately filter that many candidates in a reasonable amount of time. As it stands, using the highly flawed criteria we use, it still is an enormous drag on the firm to do hiring.

The criteria used - 'elite' school, impressive extracurriculars, good grades - were selected because of their performance in a quality-time trade off. Your choice in reading resumes is to do a good job with 90% accuracy at 15-20 minutes per resume vs a quick filter with 30% accuracy at 1-2 minutes per resume. With hundreds of applications to read through, which would you prefer?