Article misses the fact that a lot of governments in the 70s and 80s (shoutout to Germany especially) put a lot of investment into solar panel adoption, which is part of why the cost dropped so much in the 80s and 90s and 2000s.
[1] https://en.wikipedia.org/wiki/Solar_power_in_Germany#Generat...
[2] https://wiki.energytransition.org/wiki/history-of-the-energi...
It's also interesting that we're talking about 1980/90. 25 years ago is 1999.
So starting maybe in the 1970s would produce the current performance and economies of scale, but much earlier, not "starting" in 1999.