This. Interviewing for a sr dev position with a web app, backend stack is the bog standard java, spring, SQL abstracted away via JPA. We did a first screen, then the tech interview was two of their senior devs shoulder surfing me as I built a simple API. We chatted, I built, they asked questions, I defended my decisions (sometimes successfully, sometimes gracefully conceding defeat), they left knowing that I was who my resume said I was and the reminder that popped up in the middle of the interview to feed my sourdough starter showed them that I'm a culture fit.

I think you're onto something with that last paragraph but I want to try being a bit more generous with why things are the way they are. The question seems to be "When there are hundreds of applicants how do we give everyone a fair shake without hiring an entire team of devs who do nothing but interview?" From that perspective the intentionality is different and even sensible but the end product is likely to be the same. Even when someone is chasing a metric it's because someone else wants what's best and has decided that metric is a sensible way to make that happen. At the end of the day they really do want to hire the best candidate out of a pool whose size is extremely variable and that's challenging.