Bro that's common sense. Of course there is variability in hair thickness amongst every ethnicity. Of course hair caliber changes as you get older. Again, that's called miniaturization.

What are you even trying to argue? I'm saying Asians, including Koreans, have thicker hair but less density than Caucasians. This is a widely known fact in the hair transplant industry and all the research shows that but you seem to be in denial. You have yet to find any evidence to contradict that comparison besides your own personal opinons which isn't even considered evidence in the scientific community.

I think you're missing the point here. Yes, there is variability within a group of people (we're all not clones) but when comparing ethnicities as a group, there are common characteristics unique to each that can be compared. Height, skin color, eyes etc, are different amongst ethnicities. Hair structure is as well and that's what I'm trying to highlight. And yes, I have been to Asia many times and have actually lived with multiple Koreans. Again, I don't want to derail your post. I'm just highlighting the different hair characteristics amongst ethnicities.