I've had this same experience. Per the resume, 12+ years of experience coding and leading teams. In the course of the interview, I got a whiff of "I think this guy is full of it" so I asked him to write a simple algorithm on the whiteboard. "Write a function that takes a list of integers and return their sum." In many ways, simpler than fizz-buzz. Candidate couldn't even get started.

So how does this happen? If these candidates were gainfully employed, perhaps that indicates their roles, perhaps their entire careers, didn’t require programming? Or perhaps it means that it’s possible to write code without having a deep understanding?

These widespread anecdotes should inspire reflection, not just on the utility of technical interviews, but on the very nature of the work that goes on in the software industry. What exactly is going on.

I have no idea, but it’s possible the entire resume was a fabrication. (I had another colleague interview someone who claimed to have worked for a small IT consulting shop for a few years. Turns out she’d worked there in that time, so asked the guy to describe what he did there, then after a few minutes cut him off and casually mentioned that, of the two of them, she was the one who actually had worked there.)

I've never had that happen to me, and I hired a fair number of people over the years. To me it always seemed like a scare story of what might happen if you didn't do loads of algorithm questions.

Everyone I hired could do the work, regardless of whether I asked them algo stuff. The only people who didn't work out had non technical motivation issues.

I guess there's always another side to experience, because it seems like you've come across this a lot.