Sherpa is a subset of the Nepalese population on the Tibetian plateau that has developed over 30,000 years. During that time lots of adaptations to higher altitudes have developed. Given that the plateau averages 4500m high (approx 15,000") is a pretty strong selection pressure environment.
It's a bit more than just acclimatized to the conditions it's genetics.
https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2019.01116/full
Sherpa is a subset of the Nepalese population on the Tibetian plateau that has developed over 30,000 years. During that time lots of adaptations to higher altitudes have developed. Given that the plateau averages 4500m high (approx 15,000") is a pretty strong selection pressure environment.