I have a hard time believing that for programmers. 10x maybe, not 100x. If this were true, they should be making tremendously more than median programmers. When was the last time you heard about a software engineer employee making over $1m, let alone $10m?
Employers don't have any incentive to pay an especially effective programmer at whatever his "market rate" actually is. They just need to pay enough to fill their position with someone skilled, and there's plenty of programmers who'll take the near-guarantee of $MaxSalary/yr and live happily. ("After you've got enough to settle down and buy hardware whenever you need it, what else do you need?") If you want to realize your full "fair market value" (which is just a convenient theoretical fiction anyway), you need to take matters into your own hands.
I also don't think there's a consistent 100x variation in overall productivity/output, but maybe something more like maximum productivity (and edited the grandparent post). If you have a super-productive employee it's going to be hard to "fully saturate the pipeline" since any one single project isn't going to constantly require that level of work, and you can't just have him hop project to project within the company since there's a learning curve each time.
I originally picked up the "programmer productivity varies a lot" meme from one of PG's essays, but have since seen it in industry: http://paulgraham.com/gh.html
Peopleware claims 10x.
Anyway, Paul Graham wrote a pretty convincing essay about this.
Exactly. employees don't make make over $1m, but plenty of founders who sold startups have.