1. There are people who are 10x better at working in one codebase simply because they have so much experience with it.
2. There are people who end up leading a great lab. The sum total of their circumstances end up making them 10x more productive than their colleagues in their field of research.
3. There are people who can be dropped into an unknown research/development environment and be productive 10x faster than others.
I think people mostly mean 3. when they talk about the 10x programmer. Anyway, does any of this really matter? If you are a 10x programmer, then you should make sure you get compensated for it. And if you aren't, you really do not want to get confused for one as the pressure of expectations will make your life miserable.
I personally believe most people reach their optimum lifestyle subconsciously. A 10x programmer gets there because (he (or she) is naturally talented) and he has enough interest, desire and willingness to commit his time to become 10x better. If you aren't a 10x you probably also do not really want to be a 10x, because you probably value spending your time elsewhere or just do not truly enjoy the stress that comes with such a role.
Basically what I want to say with all of this is:
1. There are definitely some people who are heads and shoulders above others.
2. But in many cases a 10x is a 10x in their natural environment. If you remove them from their natural environment they won't replicate their success, even if their natural ability is also very much above average. We tend to attribute all the merit to the leader and forget all the people working under him.
3. You shouldn't concern yourself with how high you rank in this hierarchy. Do what you feel comfortable doing and enjoy life. You probably subconsciously chose the role that most accommodates your lifestyle, anyway.
I think I might have veered a bit off-topic.