What you’re saying makes sense but only for a planned state economy where the government owns (or subsidizes) all generation. It’s not possible in a free market economy, the nukes would go bankrupt/ never be built
Some Canadian provinces have IPPs -- Independent Private-Power companies but they are often operating under the patronage of government. Many owe their existence to privatisation, lobbying and sweetheart contracts. (E.g. in British Columbia, private run-of-river hydro companies scandalously secured a 60 year guaranteed non-market rate on electricity. https://thetyee.ca/Opinion/2016/09/12/BC-Hydro-Public-Intere... )
If “or controlled by” means privately owned plants that are subject to local regulations, then that is not particularly interesting or relevant to the discussion
They can’t cope with variable load, they can’t cope with other sources. They are only remotely viable with large amounts of storage.