Cosmopolitism is a complicated issue. Imagine a peasant from around -200AD coming to Rome. It would probably be unbelievable. His first thought, certainly: “how do they feed so much people?”
If you want to live in a big city, you probably love so-called “civilization”. Sophistication. But still, the fact that your peers are more competent also means that they are better able to steal from you.
To want a city so big, so developed, so complex, must have been a difficult dream to dream up. The idea must have been hard to get to. Still it is taken for granted now.