Who says Kenyans have superior genetics?
Posters should revel in Kenya's depth of talent. The AIU (e.g. Brett Clothier) says Kenya has depth, using phrases like "Kenya's unique problem is the sheer abundance of talent" and "In Kenya, there is a huge pyramid of top-class athletes" and "That pyramid is hundreds, or even thousands, of athletes".
What has changed is the increased testing of lower tier runners. Again the AIU (Brett Clothier) explains "In the past we have been testing the top of that pyramid, but the bottom ones have not been subject to out-of-competition testing." and this causes pressure also at the top: "So even though we are controlling the ones at the top very well and are capable of catching cheaters, because of the pressure from the athletes below, who aren't being tested out of competition, the athletes at the top are taking risks and there is pressure to stay on top".
"Kenyan doping: Why positive tests are the start of the solution"