Tech is very cargo cultish, which comes from having a young average age, and a strong survivorship bias in the media. Remember the Google brainteasers? Fizzbuzz? "Culture fit"? Tech companies have the lowest infrastructure costs of any industry, and so they have no place to hang their risk aversive paranoia except on personnel (the safer you are, the more trivial the things you fear). There's nothing logical about it…
Amazon literally has a research team focused in hiring, and they run A/B experiments to continually improve the process. The current interview format is not a cargo cult, is a high refine process through the years.
Is it perfect? hell no, but it isn't the mindless copycat people make it to be. They have actual data to back up what works and what doesn't, although it might take several years to happen (like when Google finally dropped brain teasers).