The limitations of measurements was something I covered in my 2015 RMAF talk, "What the specs don't tell you and why." And I only scratched the surface in that talk. I sold audio test gear for 15 years and sat on standards committees too. In a nutshell, we measure what we do because we can do so easily. It is my opinion that we can get A LOT more from instrumentation but choose not to because the financial reward for doing so is not there.