true. and the national boundaries mask other factors.
i believe that Northern Kenya is were most of the “ethic Sudanese” are. (Muslims.)
and just as in India, Indonesia, etc., even when the ethnic background is identical, there is a huge difference in prosperity between Muslims and non-Muslims.
England might be an even better example.
comparing Indians in England,
even when they are ethnically the same,
and culturally similar, is amazing.
The difference between Christian and Hindu “asians”,
and Muslim “asians”, is VAST...
the single explaining difference,
is Islam.