The assumption that baseline power is necessary seem like an unwarranted assumption to me, an idea that is unquestioned because that's the way things are done now. Maybe adequate provisioning of sufficiently uncorrelated, variable power sources combined with some storage is enough to replace all baseline and peak power sources. Maybe this can be done with less expense than nuclear + peaker plants. I haven't seen any nuclear proponents defend the necessity of the baseline power concept with an actual analysis showing that alternatives can't work though.