I think it’s helpful to know what the “best numbers” are though. From my perspective, it’s helpful to see that there’s actually no reason to aim for a flat line through lunch. It’s okay if your blood sugar goes up to 130 or 140 after the meal. In fact, the upper bound for breakfast in that chart (2 SD from mean) was 160!
It may not be possible to obtain the non-D average fasting blood glucose level, but it was incredibly helpful for me to see a clinical study documenting normal glucose patterns so I could set goals based on what would be healthy and normal for someone without diabetes.
I actually think that it’s critical to base your goals on what you would experience if you didn’t have this chronic illness. The analogy of a pilot and a bird is an over-exaggeration.
I do agree that the A1c is over-utilized and it would be better to target pre-prandial and post-prandial glucose levels. At the same glucose levels over a three month time frame, two people could have very different A1cs. That makes using it as a guide for treatment a major problem.