This analysis [1] shows that building tunnels in the US costs 10X more than in Norway, and 3X the average for the countries studied. Obviously, this means that with the same government budget, you get 10% the infrastructure than a country like Norway. However, this also means the return on investment needs to be 10X higher to justify starting the project at all!
This trend holds true for most types of building projects in the US.
Availability of cheap skilled labor. Europe often sources it's cheap engineers and Trades workers from the East.
Inefficient regulatory Frameworks such as mandated workers to do nothing and an onerous environmental monitoring.
Political dysfunction and gridlock. Projects are often poorly conceived and continually change their design and intent over the course of a project.
Some of these might be considered Network effects I guess. If you don't build infrastructure, you don't have a healthy market for workers and companies with expertise
As a separate question, I don't know that the European socialized Healthcare Services are paying for the migrant workers from Eastern countries that perform the work
Back then we would have just built a whole new bridge somewhere nearby and then probably detonated the old one.