Because a mix of renewables deployed on a continent (most grids tend nowadays to extend on whole continents because it enhances continuity of service while offering many ways to optimize for emissions, costs...) is better (cheaper, less dependency towards any fuel, less risk related to accidents/neglects/mistakes/war/terrorism/hot waste/... ...).
Building and running a nuclear reactor involves a lot of physical activity. And if the past is an indicator, we always move from physical activity to the flow of electrons.
The discussion about nuclear vs solar remind me of the discussions about spinning HDs versus solid state drives when they were new.
