Nope, you can't reduce the differences between people's skills into "they had more years of experience with X (but fewer with Y)".
First, there are people who spent decades working with the same technologies, and still somehow failed to learn the essentials. Some people simply have almost zero curiosity and zero desire to self-improve. (Giving specific examples is risky, because they sound completely made up. An Oracle database expert, who doesn't understand the necessity of having a primary key? A Java developer who never heard about Map, so he kept implementing it over and over again as a set of methods, for each variable separately?) Being 10x more productive than these people is quite simple. But it is also possible to be 10x more productive than the average developer.
Just consider than "10x more productive" doesn't necessarily mean typing on the keyboard 10x faster. You can save time by using a library; this includes understanding and using the standard libraries instead of reinventing the wheel. You can save time by using the right abstraction, instead of copy-pasting all over the code. You can save other people's time by documenting the code you wrote. You can save testing time by writing unit tests. You can save everyone's time in the future by having a clear project architecture. -- Furthermore, you can increase the team's productivity by teaching your colleagues at least the basics of these skills.
There are people who are this good at the things they do regularly. (Which also happen to be the things I do regularly, so it is humiliating to see the level of skill I will probably never reach.) And they can still learn new things with at least the same speed as anyone else around them.
Neither of those examples surprise me that much. It’s not that uncommon that being able to produce something that vaguely works well navigating a messed up organization is what it takes to be productive. The bar on not being a totally messed up organization is low but tons of places don’t clear it.
...otherwise - being a bit of a history nerd - I’ve run into the idea many times in discussion of how military units have evolved over time. Much of the thinking about ideal squad sizes began in WW2 - don’t have single thing I can point you at though
From my professional experience, it’s obvious that there are coworkers that can output even 100x impact qhen compared to peers. When judging entrepreneurs it’s visible some people’s multiplier/productivity is in the million-times compared to others.
Given automation is at the core of our work as devs, why do some people think 10x isn’t credible?
In my experience it's a lot more common that I see people churning out 10x the AMOUNT of code (or some other insane metric) which generates an enormous amount of work for everyone else to keep up with, fix, maintain, understand, etc. These people are praised for their output. But are they making the TEAM 10x more productive? No way.
Prolific output doesn't always mean 10x value created. I know people know this, but I think the reason people are sick of the trope is because they've been burned by a "10x'er" that was all output, not actual value.
Producing 10x value is actually.. really, really hard.
As a practical example, consider 4 people beating Windows Mobile with what later became Android.
They did this by breaking systems (DNS, build pipelines, etc), producing code so bad that it had to be rewritten from scratch, and distracting everyone on the team through drama.
They also did it through endless requests for help - not the kind where they learn from it, though. The kind where they ask the exact same question next week of someone else. They would cycle through asking everyone on the team about the minutiae of their job, because they had no idea how to do it themselves.
I realise that the idea of the '10x rockstar' is an unpleasant one. But I also know that the best people I've worked with over the years were at least ten times better than the worst.
Let me add that I enjoy teaching folks, that I enjoy being a multiplier even if it means I won’t be an additive. I am also an apologist, and willing to believe that people are adding important ingredients to a team or output that aren’t immediately obvious or visible.
But -x folks exist.
Unfortunately the -x folks often DO have significant skills at hiding their negative impact.
In all seriousness, is it time to get rid of the 10x meme? People have strengths and weaknesses; people have areas they've experienced before and things they've never done. Some people are going to work faster than other people on certain tasks - that's life.