Earlier quoted context omitted.
Yes, I don't think their process is magic. Google gets a good workforce because they are generous and prestigious, which means a lot of good people apply there. And Google is willing to say no to a lot of people in their search for good people. They reject a lot of candidates who would probably have worked out just fine.
Or, put another way, they choose to accept a high rate of false negatives to avoid false positives.
Which is how it is typically presented because it sounds much better than "reject a lot of candidates who would probably have worked out just fine". It is useful to perceive both the potential value in an approach like this and the shortcomings. Google can absorb the massive expense in man hours, lost opportunity, etc. that comes with trying to craft genuinely predictive interview processes, but a lot of the companies trying to emulate them can't. Too often, interviewees don't realize a process of this sort is stacked against them, and interviewers don't appreciate the negatives of adopting a still-nascent approach that sounds more reliable simply because it is quantitative - and assuming since Google does it it must work.