What’s even a “10x profession”?

Jobs where the difference in output between the best and worst is 10x. Generally creative professions like movie director, writer/journalist, lawyer, etc. SWE tends to fall into this category because the difficulty of writing good code is in some respects like writing good prose: the space of "solutions" is vast and there are few well defined rules by which a "good" solution can be constructed. Not only that, but writing it quickly while maintaining quality is difficult as well.

See for example this blog by Joel Spolsky [1].

[1] https://www.joelonsoftware.com/2005/07/25/hitting-the-high-n...

Something software engineers came up with to feel exceptional. There’re great people in most professions, but this “10x” concept is completely subjective and not quantifiable.

The link provides empirical data backing up the idea of 10x, specifically in the context of the speed and quality with which students come up with solutions to a programming project. Quality is measured by correctness and speed by time spent.

It also provides data showing that speed and correctness are essentially uncorrelated between different people - i.e. just because two different people finish at different speeds, does not mean the faster person has a less correct solution, at least in this specific setting. If you assume that's true generally, that makes the idea that there is a large gap between F500 programmers and FAANG ones even more credible, since the best programmers both produce better solutions and produce them faster.