FIRST, LET US NOT FORGET THAT THIS IS A THREAD ABOUT MERRITT, AND ABOUT WHAT YOU DON'T KNOW ABOUT 7 VS 8 STEPS.
With that out of the way, I consider your latest response to my flame.
I read through the article to which you initially linked. Its contents assessed physiologic adaptations to high-altitude stressors among 3 populations, including select Andeans, Tibetans, and Ethiopians.
The paper reports that "Represented by a single study, the Ethiopian pattern is distinguished by levels of hemoglobin concentration, oxygen saturation, and arterial oxygen content comparable to those of healthy sea-level populations." Whereas the Andean population showed an increasing response with increasing altitude, the Tibetans only showed a response when living above the altitude at which the Ethiopians lived. In total, the Ethiopian population was the same as the Tibetan population, but with a 10% higher arterial oxygen content for the same altitude. Their arterial oxygen content was likely the same as the Andean sample for the same altitude, but using a lower hemoglobin concentration.
These results are relevant only to patterns of adaptation to the high-altitude stressor of hypobaric hypoxia. The study indicates that the Ethiopian population, within the limits of the study and compared to only 2 other groups, showed a different pattern of adaptation to this altitude-related stressor, which in shorthand means a different phenotype of arterial oxygen content. This would suggest a different physiologic adaptation, but does not suggest that they have an intrinsically different oxygen delivery physiology. The author, in a companion paper, explicitly limits this different physiology to those situations requiring adaptation to high-altitude conditions: "Ethiopians must have unique ADAPTATIONS [emphasis mine] of oxygen uptake or delivery that result in the absence of an hypoxemic stimulus to increase red blood cell production and hemoglobin concentration despite their high-altitude residence."
Significantly, the author in a cited paper stated that "The Ambaras highlanders had an average oxygen saturation of 95.3 ± 0.2% with a range from 88 to 99 (n = 209) that was slightly lower than that among Ethiopian migrants residing near sea level (207 m in Cleveland) who had an average oxygen saturation of 96.7 ± 0.2% (n = 48) (t = 4.1, df = 255, P < 0.05). That is, the Ambaras Ethiopian sample exhibited clinically minimal but statistically significant arterial hypoxemia despite residing at 3,530 m (11,650 feet), where the partial pressure of inspired oxygen is one-third lower than sea level." "Statistically significant" means that they're not as different after all, as they exhibit the same type of response as does the Tibetan population.
Although the physiologic difference is limited by the studies to adaptive situations, it will be interesting to see if it does, indeed, result in a different physiology of oxygen diffusion into the blood. The author states that "The mechanism for achieving the high oxygen saturation is unknown. The flow of gas along the oxygen transport chain is proportional to pressure differences and conductance between the links and thus suggests there is high conductance from the lung to the blood. Hypothetically, this could result from higher diffusion from alveoli to pulmonary blood and/or higher oxygen affinity for hemoglobin. The latter could potentially result from a mutant form of hemoglobin, lower 2,3-diphosphoglycerate or respiratory alkalosis secondary to marked hyperventilation. Because all had normal hemoglobin A by electrophoresis, the possibility of a high oxygen affinity variant of hemoglobin can be excluded (24). Future study of Ethiopian samples spanning the inhabited altitude range from sea level to ≈4,000 m are necessary to confirm and explain these findings."
So they rule out a different form of hemoglobin, but leave open other possibilities.
Regarding whatever it was that you quoted from Google, the statement that "The variation in high-altitude physiology among populations originating from different geographic regions suggests that there may be different biological mechanisms playing a role in high-altitude adaptation in these populations." confirms that it is limited to high-altitude adaptation.
Further, in whatever you quoted, the statement that "Hemoglobin levels and oxygen saturation in high-altitude Ethiopians living in the Ambaras area (3,530 meters) have been reported to not significantly differ from those in low-altitude residents in the United States [4,5]." appears to be explicitly contradicted by the cited paper above, which again stated that "...the Ambaras Ethiopian sample exhibited...statistically significant arterial hypoxemia despite residing at 3,530 m".
I repeat once more: this is expressly limited by the authors to high-altitude adaptation, even as quoted in your Google reference: "Our combined results suggest that the genes and genetic variants CONTRIBUTING TO HIGH-ALTITUDE ADAPTATION [emphasis mine] in Ethiopia are largely distinct from other high-altitude regions...", and even at that, are only distinct with respect to the 2 other high-altitude populations studied.
None of this in any way indicates that their oxygen delivery physiology in anything other than high-altitude adaptation situations is any different from anybody else's, let alone that even if it were, that it would lead to enhanced athletic ability in endurance events.
Don't get me wrong--I'm a firm believer that they are "just better", for whatever reason. I acknowledge that they might even have a different, athletically-superior oxygen delivery physiology--but the studies you are citing do not support any such proposition as far as I can tell.
Again, DID YOU EVEN READ THE PAPER, OR ARE YOU RELYING ON INTERPRETATIONS YOU FIND OF IT ON THE WEB?
You might want to try COGNATING instead of GOOGLING.