I've also been kinda curious about the research in favor of structured interviews, because as far as I've seen they're generally drawing their conclusions based on "predicted performance" vs "actual performance".

How the heck do you measure actual performance? Income / promotions / etc is very frequently a horrifically biased metric, for similar reasons to interviews. It seems like there's a pretty good chance they're just measuring relative bias between interviewers and the interviewee's management, and concluding interviews are done poorly when they disagree with management.

I don't think management is in general a good measurer of technical skills. So the research seems to be pushing for "interviews that force you to think like a manager" rather than "interviews that find skilled individuals".