scifi setting idea: movement from rural areas and small cities to larger cities continues until approximately everyone lives in one of like 10 different megacities; all of the farmland and oil fields and mines and whatnot in between are 99% roboticized, with only occasional human repairs; all of the cities are tightly connected by supersonic travel, which becomes more feasible because there are very few people on the ground outside cities to get annoyed by the noise; drugs solve sleep and allow effortless adaptation to jet lag. uniquely, SF nether expands to become a megacity, nor disappears into irrelevance; housing becomes so absurdly expensive that only the very best researchers and engineers can afford to live there, causing a huge selection effect towards talent density.