"New York’s Second Avenue Subway cost $2.6 billion per mile... The approximate range of underground rail construction costs in continental Europe and Japan is between $100 million per mile, at the lowest end, and $1 billion at the highest. Most subway lines cluster in the range of $200 million to $500 million per mile."
I think the point is that while you can find your pet example of an over-budget project, other people can find examples of projects that didn't have those problems.
Rushing to post "but what about the Second Avenue Subway" in any thread on this topic is not useful, since you've provided no evidence that it's representative enough to generalize to all infrastructure projects in all cities of all states of the US.
It's well known that infrastructure projects in the US overall cost way more than comparable projects do in most of the rest of the developed world. Here's just one link, from a cursory Google:
"New York’s Second Avenue Subway cost $2.6 billion per mile... The approximate range of underground rail construction costs in continental Europe and Japan is between $100 million per mile, at the lowest end, and $1 billion at the highest. Most subway lines cluster in the range of $200 million to $500 million per mile."
https://www.citylab.com/transportation/2018/01/why-its-so-ex...