Edit: Gemini took 4 years from project submission and 2 years from construction start. Vogtle took 19 years from project submission and 12 years from construction start.
A standardized reactor design and regulatory certainty would enable the economies of scale and accrual of institutional knowledge to efficiently build new power plants. In response to the 1973 oil crisis, France massively expanded their fleet of nuclear reactors which were producing more than 70% of their electricity in about 15 years. If the political will is there, it can be done.
China does similar projects in about 6 months. IOW, China does solar projects about 8X as fast as the US. OTOH it does nuclear projects in about 5 years, about 4X as fast as the US.
France is experiencing exactly the same long delays and cost overruns today at Flamanville, despite having a welcoming regulatory environment, etc.
China also has lots of delays, and presumably cost overruns, but costs are a hard thing to pin down in China. China is barely expanding their nuclear program, only something like 50 new reactors are planned, a few orders of magnitude smaller than their plans for solar and wind.
CA HSR has experienced the obstructionism that Vogtle did not, but is still making good progress. The media narrative doesn't cover it well, but there are new sections completed all the time.
We have problems with big construction projects in the US, but nuclear takes those problems to the next level. And we have great non-construction alternatives for nuclear.
This is not a good parallel as the HSR's cost comes in large part from traversing many counties, municipalities, and private land.