The regulation is basically a liability shield and subsidy, the industry wants more, not less, of it to build plants.
And if wishes were horses .... It's hard to imagine how any democratic society could have gotten past the salience bias to make that happen. (Also, there's the better-the-devil-you-know familiarity bias working in coal's favor, to say nothing of the political influence of voters depending directly or indirectly on coal for their livelihoods.)
EDIT: This also brought to mind the trolley problem [0], with the added wrinkle that it's not possible to predict with any confidence which specific persons would actually be injured or killed.
Are African and Latin American countries with less effective governments and less regulation are leading the world in innovation, cheap nuclear power, genetic engineering and so on?
A casual disregard for the living and a "happily ever after" fairy tale correlates pretty well with a lot of cult and religious behaviours, and associated human tragedies, but not very well with actual happily ever after, I think.
Restating it isn't convincing. Innovation didn't stop when slavery was banned, innovation didn't stop when Romans mandated that bread sellers sold a fair amount of bread, or when weights and measures were standardised in commercial transactions, or when mains electrical devices had to be earthed/grounded/double-insulated.
"You can't pollute groundwater with careless discharge of nuclear waste" - innovate within that constraint.
We shouldn't be rewriting history now that we see that nuclear power could have actually prevented global climate change.
...and the fact we have about 4bn more people here than we did in 1960.
So, no, population (at least high population) isn't something that was unforeseen.
They simply didn't take into account all of the associated costs and complexities that would be involved with the actual nuclear power plants, not to mention the political and social complications.
That doesn't mean such a future can never happen, it's theoretically possible. We're simply in a place right now where it's hard to imagine with our current level of technology and our current energy economy.