We no longer have a broad reservoir/cadre/pool of practitioners of engineers, construction crews, experts, designers (except for a very concentrated few) who do this week in, week out. Every job now seems custom. Only Parsons or whoever has the ability to do it, and even they have to scrounge around for the project manager.
Other countries are in their building phase and have thousands of engineers who are practiced in standardizing designs and squeezing out inefficiencies. They have graduating classes full of highway engineers. For gods sake, they even have graduating classes full of engineers specializing in the tooling for highway / railroad engineering machinery.
Our building phase was post-war construction-crazy economic expansion era. Now we're in the maintenance phase, where big new projects are the exception. Not to denigrate the great importance of doing great maintenance, but in practice you can't keep (or attract) a large pool of well paid expert engineers going on that level of activity. They go where the projects go.
And as a result, as the report points out, when everything is "for the first time again" and custom because you do it once per decade, the particular factors of a given site are allowed to dictate what the system design should be. (Maybe also not insignificant: the environmental considerations allowed to creep in, just to point that out, as grateful as I am for the protection that we give these matters). Rather than (for better or worse, probably a bit worse) in other countries, they're stamping out highways, railroad, power plants by the week, and the environment is made to fit the construction.
It's choices we made, over time, that caused us to atrophy our capabilities here. It could be brought back with investment.