It's not just about the cost. The mix of nuclear and locally-available gas and hydroelectric makes for a self-sufficient energy strategy, and that has always been a major concern. Yes, Ontario is synchronized with the US grid but it could disconnect if necessary. Electricity is a valuable but not critical export economically.
As with France, a substantial influence on historic policy was to build surplus generation for economic security reasons. Could have just imported coal and oil. But Ontario does not have much coal or oil. Same with Quebec and hydroelectric.
Renewables provide the same sort of decentralized benefit, of course.
At the scale of the worldwide electricity grid cost is a major concern.
If the difference was a few billion globally then that’s trivial compared to the issues from climate change, but you can’t hand wave things once the difference starts crossing into the trillions.
France was able to heavily subsidize Nuclear and while their economy took a real hit it wasn’t such a big deal. Bangladesh and other developing countries simply aren’t capable of making those kinds of trade offs and nobody is going to subsidize nuclear power in the 3rd world on the scale they would need.
As with France, a substantial influence on historic policy was to build surplus generation for economic security reasons. Could have just imported coal and oil. But Ontario does not have much coal or oil. Same with Quebec and hydroelectric.
Renewables provide the same sort of decentralized benefit, of course.