Not an engineer but, if your infrastructure is that old first of all I'd focus on maintenance, rather than having dick measuring contests with countries that have questionable attitudes towards pollution, safety and nature.
The condition of the roads and infrastructure in a large part of the US is very, very bad when compared to countries like the Netherlands. It’s like the US is a superpower with third world infrastructure.
Maintenance of old infrastructure in large projects is difficult and budget for this purpose is hard to justify, while building new things gets harder due to (self imposed) new regulations and higher costs (outsourcing might be cheaper, but always has some risks...).
While I agree with you 101% I think that politics play a huge factor on this: no administration wants to do its homeworks, only for the next one to profit from the shiny new infrastructure.
I believe this is a stronger factor in countries that have a maximum amount of mandates per administration.
As someone who has traveled to many third world countries in SE Asia and South America I can confidently say that the US does not have third world infrastructure. Most claims of this are frequently done by somebody pushing some kind of narrative
I agree it’s a bit hyperbolic, but as I said, the US definately has very bad infrastructure in a large part while the other parts have good or very good infrastructure. On average experts rate it with a “D”
Not only old but also not enough. In areas that population have grown a lot in the past few decades, it makes a lot of sense to build new infrastructure to keep up with the demand
