Two reasons - cost and safety worries as in Chernobyl/Fukushima/waste etc.

The safety worries lead to excessive regulation and higher costs.

Here's how it's going in the UK with Hinkley C, our first new reactor for 30 years - "EDF now estimates that the cost could hit £46bn" for one reactor. https://www.bbc.co.uk/news/business-68073279

Also while nuclear costs rise, renewables plummet https://skepticalscience.com/print.php?n=6053

From World Nuclear Industry Status Report 2024:

>Solar and wind power capacities alone grew by 73% and 51%, respectively, resulting in 460 gigawatts (GW) of combined new capacity versus the 1 GW decline in nuclear.

>In China, a major energy market, over 200 GW of solar capacity was added compared to 1 GW of additional nuclear capacity.