Solarpunk technology

examined six grid-connected solar systems installed between 1987 and 1993 across different Swiss regions

tldr, ambient heat makes a huge difference. Switzerland doesn't get that hot anywhere, and even less so in mountains.

But these are extremely old panels. Panels in 2020 started shipping with 40 and 50 year warrantees. But even panels that drop to 50% of original capacity, 60-100 years later, the best strategy for adding more power is more panels rather than ripping out and replacement. For a house, that can mean balcony solar, east/west, solar sheds, driveway awnings or solar RVs.