I had no idea that such practice existed, thanks for sharing!
Not to take away any credit from your argument but not all places on Earth have mountains nearby. Also, I assume that since these nations and people live in mountainous terrains, they had to come up with a method to dispose of those cadavers in the face of land scarcity where they live.
Tibetans also do a water burial. The first time I was there, I was asking about eating fish and birds in addition to mammals, and was told, "Tibetans do not eat fish and birds because fish and birds eat people," which I first thought was a joke.
Not to take away any credit from your argument but not all places on Earth have mountains nearby. Also, I assume that since these nations and people live in mountainous terrains, they had to come up with a method to dispose of those cadavers in the face of land scarcity where they live.