[quickthrowman]

It’s just another example of Baumol’s cost disease: https://en.wikipedia.org/wiki/Baumol_effect

Very few efficiency improvements have been made in bridge building over the past 150 years aside from prefabricating sections offsite and using hydraulic cranes. Inflation pushes wages higher, making it seem more expensive since there’s no efficiency gain, just higher wages for the workers. It’s good that the people that build bridges and roads and buildings can afford to live.

Preserving a 150 year old bridge gets complicated as it’s virtually bespoke work, problems are uncovered as the project continues, ballooning costs.