Developers are not fungible. But in my opinion: this "10x" term really has to go away. We need a better way to describe the reality that there's a range in quality and capability for developers that doesn't suggest an order of magnitude. That just means corner cutting.
I've seen order of magnitude differences in performance among developers. The baseline was competent still, mind you; it's just some people are really, really good at their job. And it's not just "oh they put 10x as much LOC while really smart people would focus on proper design": they excel both in theory and practice.
A problem however that you can't really see it in the hiring process. Unlike "0.1x developers" whom you can filter with fizzbuzz, they are indistinguishable from a normal, competent engineer in the interviews, and there aren't many of them around.
Either way, building your company to depend on being staffed by top performers is a dangerous strategy IMO.
I'm sure technical ability falls on a curve like all other human abilities/activities. Like take weight lifting. Most people will be around the middle. Some will be able to lift heavier, some will be able to lift less. But if two people are training I would not expect one person to lift "10x" the next person. No way, no how.
It is a bit silly, but try thinking of it as "one developer who helps makes ten others be twice as productive". It could even be a non-technical manager who is really good at taking care of all of the non-development work for the team, allowing them to focus on what they do best.
Why don't you think the range covers an order of magnitude? Salaries certainly do. There would have to be an explanation for why companies are behaving wildly irrationally for that to not indicate a similar range of employee output.
