The Valyrians and the Dragon Lords' Resistance to Disease

It seems like that sort of planning wouldn't have come from someone that was completely naive. Or the wall building is faster than we think, because it's this fused dragonstone thing, which implies a magical process. It might not be that big, it might be like a 50 person enclave or something, but it may have planned it being larger, and just everybody died, so they stopped. They use locals to do a lot of the labor, so the labor force building the walls maybe is,. you know, not, it doesn't put them as much risk with other laborers who would just die as well. And if they don't care what happens to their slaves, because they're huge