Maintaining existing plants can make a lot of sense in many cases, but the problem with nuclear energy has always been cost.

Compared to alternatives, the cost per kWh is high once you take into account the initial capital investment, operation, retrofits, waste storage and decommissioning costs.

For places like California, wind/solar is not only cheaper, but easier to deal with from a planning and regulatory standpoint. When you have limited time and resources to add more generation capacity, there is usually a better option.

There is always the promise of a new generation of nuclear though. It will most certainly have to get used in places that have no alternatives.