But the truth is there are people who are insanely productive relative to median, and 10x is just a rough term to refer to them.
I do think it's worth paying those people 2x or more over paying 1x for two median devs. The trick is being able to identify them accurately... that relies on a well honed interview. There's risk in compensating people so highly if your judgment turns out to be wrong.
Certainly definitions won't be universal, but this type of person tends to do very well regardless of the environment/language etc.
No, I'm not talking about the BS certifications where you can spend a few hours reading a book and pass a multiple choice test... but something more "elite" and well rounded to give a quality stamp of approval.
It would be a great thing if candidates could go through one process, get that stamp of approval, and receive offers from X companies.. rather than interviewing 100 times. I understand the needs of companies are individual, but most candidates who are "strong" will do well interchangeably at these companies... if it's more of a generic development role.
The difficult thing is that the industry seems very stuck on algorithm and design problems as the sole focus of judging a candidate, which are pretty easy to game (design less so than algorithms). To identify these kind of people you really need to judge real world code and productivity... large projects with more elements of design.
Beyond technical skill, how hardworking is the person? How much will they care? Personality traits like these tend to matter a lot more than specific knowledge.
Anyway... this is kind of a meandering response, but I do believe that in the future we'll have a much better system for interviewing with less redundancy and higher accuracy. The goal is to maximize correlation between performance on the interview and performance "on-the-job".
Say I had all those traits and you decided I was a 10x and now I've got my shiny label and I'm happy.
Then I come across someone else with a stricter definition and more requirements. They say I'm not 10x. Who do I believe?
Because there's no widely accepted standard, it just ends up being a game of finding the right people who like the qualities that you possess.