Well... yeah. To pedantically elaborate that, clearly the hypothesis is that the measured traits (doing well on a coding interview and doing well at coding) are co-causal, and that measuring one (which is comparatively cheap to do) is a useful proxy for measuring the other (extremely expensive!).

That's a really compelling hypothesis. The counter point requires, to my eyes, a clear working example: a company with a uniform hiring process involving some other technique which has a track record of product development as robust as all the existing leaders. And I don't see one. Calling them monopolies or cargo cults seems to be filling in for evidence, and I don't see that as persuasive.