[Ekaros]

One aspects to consider I think could be damage from external sources. Like freak hail storms that could be more common. If these sort of events regularly destroy panels with other accidents like fires due to failing installations average age could drop even if some panels are still functional.

Outside most extreme events nuclear plants in general are repaired if some component fails.

[bryanlarsen]

A freak hailstorm could take an entire solar farm out, but otherwise they are pretty resilient. There are pictures of Ukrainian solar installations that continue operating after missile strikes. The panels that got hit stop working, but the rest keep supplying power.