France has sort of done this - they have 56 reactors in operation all based on the same 3 basic designs[1]. It's pretty incredible how quickly the plants were designed, tested, and built. Over a span of 15 years they brought 56 reactors online[2] - in the US we'd be lucky to build and commission a single reactor in that time span.
[1] https://www.iaea.org/newscenter/news/frances-efficiency-in-t... [2] https://www.pbs.org/wgbh/pages/frontline/shows/reaction/read...