An old question running through my mind:
Displays, camera, speakers, microphones: why after more than 50 years of development do they still need calibration?
Whatever cheap or high-end material I come across in the reviews I read from time to time, none seams to be properly calibrated.
There is enough research and commercial competition over these transducer categories for a time long enough to make this intriguing…
Calibration is expensive. Regarding consumer equipment, most users want less expensive product and do not mind small deviations. If you are willing to pay, you can get very precise stuff with decades of research in it.