5 seconds of Googling shows that the Aztec and Inca both had ceremonial headdress/crown for the ultimate ruler. 5 seconds of Googling about the Maya and the Seneca did not turn up anything.

Thorstein Veblen (19th century sociologist) would probably explain the crown/headdress prevalence around the world as a form of conspicuous consumption (he coined the term). The ruler wears a ridiculous and impractical headdress that “wasted” hours and hours of labor to show his dominance, wealth, prestige and ability to waste (and coerce). I’m not a sociologist but I have read his Theory of the Leisure Class and it fits very cleanly in his theory.

Now why a crown and not a breastplate, eg? No idea. Maybe it’s simply the most conspicuous and ridiculous thing one can wear that serves absolutely no practical purpose (whereas a breast plate could be useful in war)