MIT found that reusing a design made plants more expensive to build, not less, because of costly on-site last minute design changes.
Taking your point more charitably, it is indeed the lack of a sustainable nuclear energy industry that routinely builds plants that causes costs to skyrocket. There is a chicken and egg situation: nuclear projects don’t get funded because they’re too expensive, so there is no chance to develop expertise in how to build them cheaply, which causes the few that get greenlit to be built by rookie teams that make rookie mistakes that cause costs to skyrocket.
Taking your point more charitably, it is indeed the lack of a sustainable nuclear energy industry that routinely builds plants that causes costs to skyrocket. There is a chicken and egg situation: nuclear projects don’t get funded because they’re too expensive, so there is no chance to develop expertise in how to build them cheaply, which causes the few that get greenlit to be built by rookie teams that make rookie mistakes that cause costs to skyrocket.
The MIT study into the causes of cost overruns: https://news.mit.edu/2020/reasons-nuclear-overruns-1118