It's more accurately a common law problem. European states with Napoleonic law appear to avoid the cost spiral.
> You can probably draw a line between cities and not hit many things
The empty parts are away from cities. The California and Capitol corridors are (a) prime rail routes and (b) almost contiguous megalopolises.
Germany alone has like 3 major extremely over-budget infrastructure projects I can think of.
I'm going off cost per mile to build rail and road. Even when European projects go over budget, they still clock in below the U.K.–on average–which clocks in way below the U.S. (The latter gap is best explained by institutional ineptitude.)
At least not in France. The "SNCF" had to be rescued by the French state three times since it was created in 1937. And it was created because the private companies it replaced were bankrupt. [0] (in French)
Each year the French state gives ~16 Billion Euros to the company [1] (in French)
[0] https://www.lemonde.fr/les-decodeurs/article/2018/03/19/cinq...
[1] https://fr.wikipedia.org/wiki/Soci%C3%A9t%C3%A9_nationale_de...
"European states with Napoleonic law appear to avoid the cost spiral."
Do you have any hint of other European states with Napoleonic law that avoided cost spiral?
Asking out of genuine interest - do you have any ideas as to why this might be?