I also agree that, in the name of transparency, it would have been nice to see Apple continue the practice of reporting unit sales. But, Apple is the largest or second largest corporation on earth. They must be doing some things right.
However, Apple’s decision to withhold unit sales data provides an opportunity for someone to infer unit sales from other publicly available data.
How many current and former students out there would like to take on that challenge? Could be an interesting research project…
-Dr. Moore
Apple’s iPhone Subtraction Demands Some Addition
https://www.bloomberg.com/view/articles/2018-11-29/apple-s-iphone-subtraction-demands-some-addition