Travelling all across the developed world this question’s naturally recurring. Here some likely fragments of the answer:
limits on people’s supply and demand
freeloading/happenstance
artificial
personal ability
citizenship
discrimination (racial, sexual…)
naturaldiscrimination (racial, sexual…)
unique, hard-to-learn language and culture (say Japanese)
geographic isolation
scale of marketgeographic isolation
work ethics and kata
education or experience
intellect, body and disposition
governmentseducation or experience
intellect, body and disposition
regulations
competition policies
taxation
tariffs
knowledge and application of economic metaprinciplescompetition policies
taxation
tariffs
division of labor
free trade
private property (the machinery of freedom)
social capital and infrastructurefree trade
private property (the machinery of freedom)
urbanization
tangible
exploitationtangible
access to technology
roads, telephones, public health measures…
public transportation
information technology
intangibleroads, telephones, public health measures…
public transportation
information technology
rule of law
security
public education, literacy
access to finance
intellectual property, public commons
access to legal, tradeable property (think Hernando de Soto)
security
public education, literacy
access to finance
intellectual property, public commons
access to legal, tradeable property (think Hernando de Soto)
freeloading/happenstance
like how speakers from any country that speak English get access to unique opportunities for no other reason than speaking English
natural resources (think Arab countries)
currency as investmentnatural resources (think Arab countries)
It’s a stab. Please help with more ideas that come to mind.