> After performing over 100 interviews: interviewing is thoroughly broken. I also have no idea how to actually make it better.

My score is similar, and kind of agree. The eerie part is that the intuition can discern a good hire within 2 minutes with fairly high probability, and within 10 minutes with near certainty. The rest of the interview process is just padding to figure out whether the intuition is not wrong (it seldom is).

That intuition is some mashup of the candidate speaking on point, pragmatism, non-equivocation, admission of ignorance on some topics, English proficiency (1), etc. It's also impossible to codify or quantify, hard to convey and non-transferable.

(1) - here in Europe, English fluency, diction and (lack of) thick accent correlate highly with overall ability