It's not always about being FUCKING SMART, sometimes just having a different attitude helps.
I've worked with testers who refused to write code but would rather test everything manually (and fall behind on every sprint!), while stupid (yes), you could easily come in and be a 100X more productive by just writing tests as code.
For one company I worked for we had an old legacy system (running DOS) that we used to produce master copies of our disk images. When we needed a new master it would take the better part of a day to make all parts work. I wrote a program that could do what the legacy system did but under Windows, taking a couple of seconds to run and now we could get a master image as a build artifact. I don't consider myself FUCKING SMART, quite the opposite, especially at that company with those coworkers who were despite the sound of it actually really smart, but unlike my coworkers I had not accepted the situation but felt that there must be something to do to improve it.
This is the secret sauce. The impulse to solve the higher order problem and the willingness to question fundamental assumptions in order to arrive at a solution.
Your non-10x devs might have attempted to optimize the DOS system, or maybe even introducing some kind of caching and just lived with the somewhat mitigated performance.
I took a couple of days to automate the process and reduced the deploy time to something that could be done multiple times a day and didn't require a developer. Am I FUCKING SMART? No, but I was able to see the bigger picture and realize that there are tools that could be applied to this problem.
...highly productive developers (10x or otherwise) are problem-solving at a much higher level. Their productivity won’t be apparent from a narrow test, any more than the overall skill of a world-class football player would be apparent from (say) how fast they could run the 100m dash.
The most productive developers are solving big problems, and are bringing judgment and experience to bear on essential design, architecture, and “build vs use existing library” decisions. They’re designing key abstractions that will pay dividends through the life of the project...
I have a personal theory the that the average 10x programmer is say 2.5x smarter than average, but also 4x more focused on work, netting a 2.5x4=10x total when you remove all the procrastination and general fumbling around of the average developer.
The 10x productivity comes in large part from the code they DON'T write.
That makes him twice as productive, not half.
If we change the question to are there 10x programmers within a team in some "average" company with CVs indicating roughly comparable experience, then ...
The answer is still yes, there are 10x programmers. I've witnessed it myself many times. Not so much because the highs are very high, but the lows are very low.
[0] Fabrice Bellard. John Carmack. Linus Torvalds.
Someone who's 2x smart and 2x experienced, only needs to spend 2.5x the amount of time to be a 10x programmer, and that's the realistic difference between someone who is just doing a job and someone who is following their passion.
Where you 10x more productive than other developers writing systems themselves?
Chris Sawyer wrote 99% of the code for RollerCoaster Tycoon in x86 assembly language, with the remaining one percent written in C.
RollerCoaster Tycoon was a beautiful game which still stands the test of time to this day. The fact that a single person was able to build a blockbuster-level game almost entirely by themselves in assembly is a truly impressive feat which very few programmers would even dream of undertaking.
Being a "real" 10X programmer is like being a savant. It's about being FUCKING SMART, and it's about being able to deliver a working, polished product in the same time that a normal team of ten people would be able to deliver it (or in a tenth of the time that a single person might).