Minor quibble but I think you mean East Africans, not West Africans. Also, most of the East Africans are actually from the same tribe/town in Kenya, Kalenjin.

Minor quibble but I think you mean East Africans, not West Africans. Also, most of the East Africans are actually from the same tribe/town in Kenya, Kalenjin. But your overall point, agreed. The only reason these races are not dominated by African runners is because of the low prize money involved. E.g. if Eliud Kipchoge ran a 2:01 for the first 42K he could have walked the remaining 8K and still beaten the winner of this race by an hour. Nothing against her or the other ultra pros, but the facts are as you describe.