I think your comment inadvertently illustrates how much of this comes down to how you define the baseline. I think the comparison for a world-leading marathon runner shouldn't be someone who _never_ exercises but someone who's actually put some effort into fitness (say, an amateur runner) — yes, they're faster but it's nowhere near 10x[1] — just as our baseline for a 10x developer shouldn't be someone who's never written a line of code before but the median professional developer. It's easy to get an order of magnitude win over someone who's completely inept but once you get into more realistic territory you're chasing diminishing returns pretty hard.
The other big problem here is that you're talking about a complex skill but trying to reduce it to a single number. Tellingly, most of the 10x developer examples cited are cases where they know exactly what they want to do and have near-complete control over it, which isn't exactly how most developers work. It's really hard to quantify things like teamwork or the ability to distill what people need from what they say they need, and those are core skills for most of us in a way that optimizing a 3D engine is not.
1. I've done marathon length _hikes_ in far less than a single day, and I'm far from a hard-core athlete.
I think it is probably much, much less harder (as a young, healthy person) to get from relatively unfit to running a marathon in 4:20 compared to getting from that 4:20 to the 2:10 that the elite marathon runners do. It's probably a lot more than 10x harder to go from 4h to 2h, I think. I gained a lot of respect for them when I realized that my gym treadmills' maximum speed (20Kph, which I have never managed to hit for any significant length of time) is less than the average speed to hit the current world record times.
That was my experience as a cyclist, too — when I was in my 20s it was relatively straightforward to get my average for a 100mph ride with modest hills into the low 20mph range, while the people in the Tour de France are sustaining greater speeds over mountains. Going from that dedicated amateur level to even the lowest pro tiers requires both significantly more effort and a fair amount of luck in terms of genetics, being able to afford that time, etc.
The other big problem here is that you're talking about a complex skill but trying to reduce it to a single number. Tellingly, most of the 10x developer examples cited are cases where they know exactly what they want to do and have near-complete control over it, which isn't exactly how most developers work. It's really hard to quantify things like teamwork or the ability to distill what people need from what they say they need, and those are core skills for most of us in a way that optimizing a 3D engine is not.
1. I've done marathon length _hikes_ in far less than a single day, and I'm far from a hard-core athlete.