Of course there are outliers. Nobody disputes that Jordan was a 10x basketball player (probably closer to 100x when compared against the true mean and not just among professional players). Nobody disputes that Coltrane was a 10x jazz musician. Why would software be unique among all fields by not having any outliers?
You're talking about exceptional geniuses, of which there are maybe a few dozen in a given field across an entire generation of people.
Every two-bit company is demanding "10x engineers". That is what doesn't exist. There are not tens of thousands of genius software developers in the world.
I think this is the problem, and my main concern with the overuse of "10x engineer": they don't live in a vacuum.
If you hire a 10x engineer and get him to move a button two pixels left, and then tomorrow someone else tell him to move the button two pixels right, he won't be a 10x engineer, he'll be a 0x engineer. There's a lot more involved and it compounds. An engineer knowing what to do and what not do (a skill often overlooked) can help immensely, but everyone needs plenty of support to be at their 10x.