There's a strong correlation between cities being rich and cities having good public transportation. Some might infer that being rich means they can afford to spend money on public transportation. But I contend it's the other way around: if public transport works, fewer people need to sink $6k-50k of their personal wealth into cars, and then feed them fuel, insurance and maintenance. All that money goes into local restaurants, arts, sports and culture instead. THAT is how you make a city rich.