The difference isn't only in how fast/well tasks get done, but a very good engineer will make many such tasks unnecessary altogether with better design and implementations that forego their need. Without including this aspect, the metric is a low-level one and not indicative of overall impact.
That's the point. If you don't have a metric that says "Alice is 10x better than Bob" and you don't specify a task she's better at, then what you really mean is "Alice is on average and by some unknown factor much better than Bob on the tasks she performs".
Framing it as though you have a rigorous comparison between them will mislead you into thinking about engineers as if they were fungible, like diesel generators, which is a very silly way to think about a divide-and-conquer field like software engineering where engineers develop different levels of expertise in different things.
If you're suggesting there is some underlying factor, like generalised intelligence, I'm not arguing with that! I strongly disagree that factor has anything to do with the number 10, or that engineers fall into discrete 1x and 10x camps, though. I think the phrase "10x engineer" leads to logical fallacies about performance.
I don't see where we disagree at all. I suggested 100x and at the same time didn't try to measure or spec it in any concrete way, which seems meaningless but have had enough interactions to say it has merit. I have no interest in why, unless it's something I can use to hire or train.
