Probably too much of a broad stroke to be dividing bitcoin by the earth’s entire population because that is not a real world use case. If anything you would start with numbers that assume a basic kind of independence status, ie old enough to make purchasing decisions that facilitate some sort of “lifestyle.” How many 2 year olds need to be included in the “number” is debatable. I get that there is a point to be made about scarcity and rounding off the world’s population to the nearest billion makes for easy math but the real distribution is likely quite a bit higher.