Oh GumpenKraut, I was there for most of the hysterical "almost there" of the seventies. There were no mentions of the corner being 70 years in duration then. That is something that came along in the mid to late eighties (at least publicly; academics might have been saying it to each other behind closed doors, safely out of the hearing of anyone connected with the funding bodies, since the idea began).
In fact, the most vocal public speaker on the subject in-the-know-and-in-the-trenches didn't believe Tokamak tech could *ever* deliver the goods and said so in Omni, while people cared and were watching.
But that was in the heady days of science, before the word "retcon" had been coined and popular science journalists didn't try and con us that there were already "working" nuclear fusion reactors every three months or so.