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.
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.
Just like the town, Ontario exports power to other areas and imports non nuclear power. If everyone used 50-60% nuclear there wouldn’t be anyone to export that power to on low demand weekends etc which would drive up prices. The area also has a great deal of hydroelectric power which reduces the need for peaking power plants.
Nuclear has already played a significant role in reducing climate change, but it just can’t economically scale to supply nearly as much power as wind and solar. And much worse when you have a high percentage of Wind and Solar adding Nuclear to the mix just doesn’t work very well because base load power becomes less valuable.