While regulation certainly didn't make anything easier, and can probably be blamed for some percentage of the failures, there's a loooot more to the story. As you point out, incorrect demand predictions, and long term planning set during a time of plenty can require cancellations too.
I wish I had a more authoritative book from a disinterested historian, but the best I've found as a summary is the classic 1985 Forbes article[1], which I found through Wikipedia's list [2] of cancelled projects, the list that initially made me think, "huh, TMI can't be blamed for that one, or that one..."
[1] reprint on a blog, with some weird commentary about Gore on top which can be ignored: http://blowhardwindbag.blogspot.com/2011/04/forbes-article-r...
[2] https://en.m.wikipedia.org/wiki/List_of_cancelled_nuclear_re...
Love to hear of any sources you might have too!
My current understanding is that the economics did not work out because: power company borrows x billion in capital to build a nuclear power plant, interest rates in the 80's are in the double digits, activists tie up the startup of the power plant for 5-10 years doubling the cost due to interest, power company finally drops starting the plant altogether and the public eats the loss.
Of course there are all sorts of complications to what really happened, like power consumption rates going up like crazy while AC is adopted and power companies thinking that the trend would continue forever, which didn't happen.
Have something you want to believe and you can find a narrative to fit it. This is a really hard trap to avoid and I'm sure I fall in it often.