The game known as d&d needs to have monster & combat math/mechanics designed around the idea of a DM running the game with players playing PCs not "a particular dm" using d&d as a randomization engine for writing a novel .Absolutely. I agree with you that it wouldn't work well. But the point of Bounded Accuracy was that a particular DM could do it if they really wanted to and the numbers would allow for the attempt. But you are right that I don't think anyone actually would do that and that as I mentioned, most DMs would turn that 1000 villages vs 1 dragon into a narrative scenario where they narrate the villagers fight in the background while the "party vs dragon" fight is the one that actually gets played out at the table.