As I get older, and maybe because I worked at a company whose product is “talent optimization”, I think a lot of the “10x” thing is just a function engagement and passion. That is to say it’s not entirely skill or “intelligence”. You could take the best programmer but if you point them at a project they don’t give a crap about they’ll phone it in. Point them at something they’re passionate about and they’ll have absurd impact. They’ll think of more novel solutions, test and refine those solutions, and crank out the whole thing in record time.

If you want a 10x engineer, give them work they love.