It's also for reasons with nothing to do with nuclear in particular. The US is just terrible at executing large civil projects. It costs more to build at large scales here than virtually anywhere else, for a confluence of reasons -- highly decentralized project management (state, county, federal, city governments all fighting for authority), lack of sustainable learning curves, NEPA being weaponized by NIMBYs to kill every project including environmentalist ones, plain dumb politics... you know you have a problem when you look onto the efficiency of Italian bureaucracy with envy, but meanwhile they can build e.g., rail projects at something like a third to sixth the budget the US can.

A big part of the problem is that we insist on fully custom and experimental projects. Every fucking time. We never just use the catalog builds. We never set and stick to a standard. Not even in road design, where the AASHTO green book is treated like a fucking Holy Bible -- we follow its (largely dumb and dangerous requirements while still bespoking every fucking project.