The problem is value and productivity in software (or any creative space) is hard to quantify in general. How much better is the best engineer you’ve worked with compared to the worst? 2x? 1.5x? How do you quantify that? But you know one is significantly better than the other I assume.

If you want to replace 10x with “much much better”, then ok. But the general idea is the same. Some engineers produce an outsized impact compared to their peers.