Author. I can talk in a pretty good amount of detail about how exactly our process worked, if anyone has any questions. And, to head off a concern a reviewer gave me: from 1997-2005, I was a full-time software developer; I shipped shrink-wrap boxed software on Windows and Unix in the 1990s, then appliances deployed at tier 1 ISPs. I'm a "software person" more than a "security person".
While I agreed with many of your points, I could not stop thinking what a huge time burden of implementing something like what you propose, at scale. For a growing company with several work streams and projects hungry for talent, the interview approach you posit would never work.
Another thing that came to mind is the fact that educators and cognitive scientists have been working for decades in what constitutes a good and effective test. Here you seem to claim that somehow you and your folks have "cracked" the system and have come up with a test process that's guaranteed to yield good long-term and performant workers?
Finally, I feel this approach while intended to alleviate some of the most common pain points of the interview process, it tries to reduce it to a number. While it would seem a number is plain and objective, much like a test score, it neglects to "tell the story" and unless all you want are gifted and highly skilled human automatons, you need a way to gauge "soft skills", which one would argue are as important as their core technical competency.