This means, in the Necklace, that cultures with a Technological Level that predates radio cannot expand beyond their home area. This is why Carnivales cultures are so different from each other, and why the largest political division is the City-State. When the nearest spot of habitable ground is 100,000 kilometers away, informational travel times, when your fastest sailing ships travel perhaps 170 km per day, make colonization and control of that area effectively impossible. Almost every Carnivale settlement is a thing of its own, different from every other, and sovreign.
Rasi settlements, on the other hand, differ only in detail. Their Tech Level encompasses and goes beyond radio and television. Their light speed communitcations are time lagged by at most a few seconds. Culture can be transmitted, and central control sustained, with that kind of time lag, even if it takes a few days to physically travel from either side of the Rasi nation to the center.
Since all Altisherpas live in The City - no mater that they frequently "go nomad", they too have light speed communications, and their nomad camps are never more than a few light seconds from The City. Cultural information travels easily and quickly from the center to the vast periphery, and Altisherpas are one people.
So, yes, the reason the Carnivales have such a low tech level is because I love them and their crazy myriad cultures. With better tech, they would all blend into one, and the Necklace would be the poorer for it.