Being mounted on a moving vehicle subjects them to a much more dynamic and hostile environment than having arguably better quality, fixed panels sitting in a dry desert for 25 years. I’m actually impressed that yours lasted 10 years.

Open for debate. They are mounted horizontally on the van, which makes them subject to almost no face-on wind forces at all. The aluminum frames are bolted to the van, but the van structure is metal and likely doesn't move much in terms of distances between bolts other than due to thermal expansion, which is also true of my ground-mount array (in the dry desert :)

There's more vibration on the van, but how the impacts their life compared to the months of daily 30mph+ winds hit the faces/rear of the ground mount array seems hard to tell without a lot of research (which someone may have done).

Interesting, most of the anecdata I've heard elsewhere (for residential solar) goes the other direction - that they degrade slower than expected.

You're sure there are no dead microinverters involved, right? I guess that'd be more than 20% on a van.

No microinverters involved.