Given my time with the reading & practice of Zen, Buddhism & Sanatan dharma with a lot of spiritual people, I'll answer this from a different Point of View.
Jayarava's answer is perfectly accurate to say why people in various places and cultures portray the enlightened Master the look up to in different ways.
it feels a bit like a Hollywood plot where it's always only an all
American hero that fights off the alien invasion of planet Earth.
A lovely thing I remember hearing some time back if you want to learn:
- Marketing - Americans
- Manufacturing, Precision, Quality - Germans / Japanese
- and so on..
India, or I will refer to a more accurate word for the region currently labeled by the British as India; Bharat by its name & history has been the center of spiritual evolution & wisdom; flavors of knowledge & wisdom have emanated from that region.
Each person & place has to play a role, something special to play its karma in the universe.
So, while Americans always fight off alien invasions courtesy of their Hollywood machinery and brilliant influence on world pop culture, silently the spiritual flavors of ancient wisdom have been reaching the corners of the world over centuries or more.
SideNote:
The word Hindu is inaccurate as it was derived from 3 pieces
that make up H-Indu-Sthan. It was the name given by those that traveled to the Indu river valley
- H - Persian / Farsiy had no way to speak / write Indu so the 'H' sound got prepended
- Indu - They meant to point to the River Indu
- For most people, things were mapped by major landmarks - Rivers, Seas, Mountains, Valleys, Forests.
- Sthan - Sanskrit loosely translate to 'Place, Spot, location'
India's name is / was - Bha-rat -
- "Bha" means Light and Knowledge,
- "rata" means “Devoted”.
Everyone, every place, every nation, every atom & molecule have to play their part in the universe which has been labeled as both:
- Nothing - Nir-guna
- Everything - Sa-guna
PS: Guna - loosely translated attributes/ properties
Given that the dharma is universal why isn't a Buddha a deva or a
Pacific islander or a woman?
Which is the reason why people traveled to spread the word.
Its also the reason why the missing years of Jesus, it is said he was in Bharat, in an area called Kashmir where his name has been found mentioned as 'Isa' or 'Issa' {pronounced: Eee- Saa - h}
Why is it also always only one person and not like say a united
nations of Buddhas?
There have always been Masters like that all over the world. If you look for them, you will see there above lies your United Nations.
Spirituality unites or actually reminds us its all one.. Union.. Yog.
Ego & material nature of human beings draws lines & divides us into Nations.
Adding a note since someone hit negative on my answer :) just because they disagree - opposite of what Buddha or any enlightened master teaches us.
So, Masters did not belong to Nations. If anything, every time a Master has come to the planet, they have come to help whoever they can reach, directly or indirectly.
Masters do not associate with Nations, Cultures or People,
It is the Nations, Cultures and People who identify with associate with a Master.
Hence, people take on rituals & rites, methods & flavors; and later even fight with other groups over those details.
Masters do not create factions, they join everyone, or should I say they are here to "remind" and "make us realize" that we are already ONE.
So, when they teach LOVE thy neighbor or Compassion, those are not for the other, but to for US, to realize the Oneness and practice it as something you are not doing for other, but for yourself :)
Hence the term "self realization", reminding and realizing that we are the all-pervasive universe - everything & nothing. :)