Having followed Vogtle and Summer very very closely, as I was very eager for e a nuclear renaissance to fight climate change, this story does not hold up.
Similarly, the "blame the regulators" game does not work for recent reactors in Finland and France based on the latest design.
What it really comes down to is incompetence on the design side and on the production side. As well as not taking the requirements seriously, at least with some of the contractors.
The design change story was more true back in the early 80s, but even then it was only part of the story. Good projects finished quickly, in any case, back then. A bigger problem was vastly over ordering nuclear too, in a planning failure.
Fundamentally, nuclear construction has to deal with the fact that in advanced economies, labor only gets more expensive and more valuable. And the foundations of big nuclear reactors are massive scale and massive labor coordination. There's so much high skill welding, that needs to be checked so thoroughly, since it needs to last so long.
There are some, like Jigar Shah, who think a nuclear industry can be built if leaders emerge who reject the blame game and take accountability onto themselves for actually making a product that utilities want to buy, and doing it on budget and on time. I'm skeptical, after having Westinghouse and the EPCs dash my hopes, and seeing the same failures in Europe at the same time. But I hope I am wrong. However I don't see a single thing in this a16z article to make me think that they will be able to pick and fund those leaders. Let the VCs be the dumb money to find a model that works, then Shah will bring the capital that can really make it scale, IMHO.