> but catastrophic enough that all the plants on this list are destroyed or rendered unusable

All the fabs on your list are fairly modern, and it is easy to see how they would be impossible to maintain in a Tainter-style collapse.

I would be looking into what you can do with ~1 um processes, which are currently accessible to amateurs. E.g. designs like https://news.ycombinator.com/item?id=11720289