I have no problem with the theory that the skull was bound by tribal tradition. And I have no trouble believing that the same tribal traditions of skull binding exist in many places all over the world with presumably no cultural interaction.
Having said that, one wonders WHY skull binding was a tribal tradition on many continents and different cultures. Hard to believe that a desire for a skull that was so abnormal compared to the natural state spontaneously occurred in relatively primitive cultures.
Well, according to Maya tradition it was considered a beauty enhancement and a mark of social status.................
https://en.wikipedia.org/wiki/Artificial_cranial_deformation
That is mysterious — there’s no sign that any human ancestors had it, and the practice grew as the trait vanished. But that’s an example of why people research. :’)