East African dominance over track events has largely ended. The 1500m world record is held by a West African, while the mile and 3000m world records are now held by white Europeans. The 5000m at the recent World Championships had no East African medalists, and the 10000m had just one. Same goes for the most recent Olympic 5000m.

Compare this with the Olympic and World Championship podiums for the 2000s and 2010s; I don't believe a non-East-African-born athlete won a single 5000/10000m medal for 20 years straight.

I'm sure the record standing so long is partially down to the fact the mile isn't run at major championships, although the middle distances like 800m and 1500m are more of an open field and not dominated by East Africans like longer distances such as 5k and 10k (Josh Kerr is already an Olympic silver medallist, finishing behind a white American and ahead of an Ethiopian-American).

Because most humans don't really try, not limited to east africans.