In my decades of experience I have yet to meet this mythical 10x or 100x programmer, but what I have seen is every once in a while somebody (probably a programmer but not necessarily) is able to take the reins in implementing a new process, or tool, or framework, or whatever, which dramatically increases productivity for the whole team. Conversely, I've seen programmers who don't try to get on board any such possible initiatives and who drag the team down as a result.

So for me, the question isn't how productive one person is. It's how productive a collective can be as they work together, and how fast is the rate of improvement over time?