but they used to be dysmal, like 30% reduction in generation capacity over 5 years.
??? Monocrystalline silicon losses less than .4% a year. That means after 50 years it's still producing 82% of when it was new. It takes 90 years to get a 30% reduction rate.
https://www.engineering.com/story/what-is-the-lifespan-of-a-solar-panel