The OP said "I also remember around 1975 getting all excited about solar and getting told that costs were dropping so fast that in five years solar would be cheaper than power produced from coal or natural gas."
That would mean PV cost parity with coal-generated electricity in the early 1980s. Actual PV cost declines have been remarkable but they didn't go that quickly.
Their memory may well have been perfect, as public speakers and newspapers do get things wrong every so often.
One show I watched as a kid, Blue Peter, introduced Thrust SSC as a car that would go faster than the speed of light. (Or perhaps my memory of that is wrong, too…)
The OP said "I also remember around 1975 getting all excited about solar and getting told that costs were dropping so fast that in five years solar would be cheaper than power produced from coal or natural gas."
That would mean PV cost parity with coal-generated electricity in the early 1980s. Actual PV cost declines have been remarkable but they didn't go that quickly.