The tech part maybe, and the tech part is only a small part of the entire interview. On top of that, since IQ tests exist, you don't need a bad proxy to test IQ

The tech part maybe, and the tech part is only a small part of the entire interview. On top of that, since IQ tests exist, you don't need a bad proxy to test IQ. Leetcode-style tech interview segments aside, that still leaves the myriad of other things happening during the hiring process which either do nothing, or function as poor proxies for other things. Personality testing through mundane questions, for example. If we're following this train of thought, since certain personality tests do have support, interviewers shouldn't be using their gut instinct to begin with.