Even with that, 20% of US electricity is still from nuclear.

We managed to build these before the industry became expensive.

Now Germany and the United States are rushing to close the operating plants.

I’m not sure why we can’t figure out how to build a standard design and replicate it

Because we can't build anything larger than an office building on time and on budget.

Perhaps because that standard design didn't work out?

Even Switzerland is shutting down nuclear plants and they managed to build the longest railroad tunnel of the world without budget overruns and half a year before due date.

In Switzerland it's a political decision same as Germany it has nothing todo with cost or the ability to run the plants.

That's not so clear cut. Mühleberg near Berne has said that 2019 they didn't make profit, however the operator company BKW never published gains with that plant.

https://www.bernerzeitung.ch/region/kanton-bern/das-akw-mueh... (paywalled)

And we've failed doing that with software for longer, yet we still keep building software.