> It is more likely that the interview process is broken and missing the right candidates, than it is that the interviewees are all mediocre.

Here's a thought experiment for you: if the interview process is so broken, why hasn't some tech company succeeded and become famous for an improved interview process, e.g. "Moneyball style"? My guess is because the process is not actually that broken, at least from the employer's perspective. I'm sure the interview process could be changed to be less regimented and more "inclusive", but that's also likely to reduce it's predictive power (i.e. you're more likely to make bad hires, and from a company's perspective that's almost always worse than missing out on a great hire).