There're nomadic "tribes" in Bolivia, Colombia, Ecuador, Peru.... all areas of very high altitude. Same thing in Mongolia, Nepal, etc
Why then are there no world class distance runners from Latin America or Asia?
Most of those places you mentioned don't have the slightest bit of training in the mountainous tribal areas. I'm not saying that they'd have runners either way, but I doubt we really know what they can do.
Also, it'd have to be a combination of high elevation AND a running culture. The places in Nepal I know about where people are at high elevation, it's not the sort of place where running would ever get picked up.
One group that seems like they could make some waves are the Tarahumara people of Mexico. There's only 50,000 of them and they're poor as hell, so they ain't got the numbers on their side, but they've destroyed folks in ultramarathons in North America just showing up and running with no real training or equipment.
They hunt deer and wild turkeys by running them to exhaustion.
Secrets of the Tarahumara
The issue with the Tarahumara ever making waves is that they don't like Olympic distances. They see 40-50km runs as sissy shyt that only women do. Their own local events involve running up to 300km in two days, and the races the men have excelled at internationally tend to be more like 100 miles. Marathon length just seems like a warmup to them.
This is what happened when some Americans brought a few of them over to compete in a 100-mile ultramarathon for the first time:
"Leadville was the venue for the American debut of the
Tarahumara runners of Mexico. In 1992 the Tarahumara first showed up to run outside their native environs. Wilderness guide Rick Fisher and ultra-runner Kitty Williams brought some of them to Leadville. However the experiment went bust. The problem, it turned out, was psychosocial, i.e. an unfamiliarity with the trail and the strange ways of the North. The Indians stood shyly at aid stations, waiting to be offered food. They held their flashlights pointed skyward, unaware that these "torches" needed to be aimed forward to illuminate the trail ahead. All five Tarahumara dropped out before the halfway point. The Tarahumara teams came back with vengeance in 1993 and 1994 and won the Leadville event outright both years. In 1993, 52-year-old Tarahumara runner Victoriano Churro came in first, followed by 41-year-old teammate Cerrildo in second. In 1994, 25-year-old Tarahumara runner Juan Herrera won in a record time of 17:30. His mark stood for 8 years until broken by Chad Ricklefs in 2002 (17:23)."
Story about it here:
Meeting the Tarahumara at the Leadville 100
Some more recent ones:
50km ultramarathon in Mexico with 500 female entrants, a 22yo Tarahumara woman won in a skirt and recycled sandals, no professional training
Woman Wins 50K In Sandals Made Of Tire Rubber
Tarahumara runner Miguel Lara has won 3 ultramarathons and placed second in 2 more in the last five years. His best races were 15 hours for 100 miles, 6:30 for 50 miles - and that ain't flat road races, that's on dirt trails going up and down hills and shyt. So you're talking about a guy who on a flat road race could easily run two 3:00 marathons back-to-back without a rest. So could he run a 2:00 marathon on its own if he trained for that pace? I doubt he'd come under 2:30...but what if you started recruiting from all the Tarahumara, and training them up at thse marathon distances from when they were young? Hard to know what would happen - none of them ever train at marathon distances or paces even though their endurance is

.
Miguel Lara's Results
It'll be interesting to see what they can do if some of them actually get solid nutrition for a couple generations and a real training program.