You don't need to carefully measure to know that no single development has led to a 10x boost. As someone who was working on large software since the late 90s, we're building things today at a similar pace, with the exception that there are many more pre-built components we just grab. Can you point to a technique/tool that has led to a 10x boost?
Precision is less valuable when the measurement is larger.
The very first piece of software I optimized, I started with “One Mississippi”, moved to a stopwatch app on my PDA, before I ever bothered with instrumentation. Because any idiot can tell 2 seconds from 3, that a boat won’t fit in the garage, or that more than double is way less than ten.
Ironically, if Brooks had said 3x instead of 10x, he might still be right and we’d have invested more in measuring things.
Well, who said his prediction turned out to be true? Who actually measured the "impact to productivity" in any quantifiable terms? And who re-did that measurement after "No Silver Bullet, Refired" (which was 25+ years ago)?