The interpretation that I like is that "10x productivity" is more about what someone doesn't do than what they do do. It's in the sense that they seem more productive, partly because they're really good at what they do, but mostly because none of what they do gets thrown away. They're good at the intangible stuff around the tangible job. Someone can be extremely productive, but they won't be "10x" if they produce a lot of stuff that ends up being useless for any one of dozens of reasons unconnected to the actual job itself.