Minimum clue level? How about the minimum level is "the level a lot of developers are making a professional living at". It's incredibly low. I've personally done things in a week that previous developers had spent several months on, and I had no particular domain knowledge. And I feel some other folks are far better than me. So the entire range could possibly be 100x.

I've had small coding issues where one dev takes a path that costs them an hour or so, and another is able to deliver the same functionality in minutes.

I've seen projects where some developers simply say " I've no idea on even how to start such a project ", and other developers sit and think, read, and end up delivering. That's far more than 10x.

Environment may be huge, but it's blatantly false to say there is not a massive, order of magnitude difference between individuals. Unless you define developer as meaning within a certain competency bracket. At which point it's only true on definition.