You really are braindead, aren’t you? How did you get this way?
As we don’t know exactlywhat the reason/reasons are for improved performance amongst Europeans and the strong performances of East African-descended athletes in the West, we are free to speculate here. Social phenomena generally have multiple, not singular causes. Here are just a few possible explanations. In the real world, as opposed to your narrow mind, most of these are not mutually exclusive of one another:
-Increased European participation in distance running
-A phenomenal Norwegian talent burst on the scene, taking the running world by storm
-Media attention garnered by Jakob inspires other non-East African runners
-East African-descended athletes in the West have a lot of talent and excellent institutional support and it is evident in yheir performances at every youth level and professionally in North America and Europe
-Europeans are doping more
-East Africans are doping less
-Kenyan officials are cracking down more on dopers
-Hugo Chavez’s ghost injected Ethiopian EPO into Athing Mu in New Jersey in 2014 while she was at a K-pop concert.
-Poor race tactics or simple failure of nerve have led to losses in specific global championships; conversely, runners not expected to win big one-off races have proven tactically superior or have taken advantage of the lack of poise amongst their opponents
-Covid and Geopolitical conflicts impact training, etc., with up-and-coming athletes from poor or war torn countries adversely impacted by instability