Any cost to a city that doesn’t have immediate utility to the people governing the city has to fight an uphill battle against everything else. And a in a lot of cases all available money is already allocated. In such an environment people generally don’t choose to make long term investments. Cheaper is easier to sell politically. And if large projects like a subway get greenlit it’s usually for an unrealistically low budget and the project ends up costing 2 or 3 times more because it’s easier to raise taxes based on sunk cost than careful planning.

Thanks - that's a hell of a lot better than the original comment. I disagree, though. Officials are elected based on projects they want to undertake. Nobody is saying "I'm beating the national average cost of building a bridge by 17%!!" in their campaigns, they're saying they're gonna build a bridge. And it'll be damn impressive. A legacy, even. Might put my own name on it.