I know old Stone Face would be completely outclassed by a lot of the setting, but aside from his high import, how would you model Mega City one and the other megalopoli in SA2?
I'd go with them being a Cargo Cult. This option seems to adapt well to their environment mixing a postapocalyptic wasteland landscape with a few oases of relatively advanced urban civilization (by postcyberpunk standards) and patchwork technology they hoard, but they don't seem especially apt to improve upon nor expand. And their social system seems static and inflexible. All of this screams Cargo Cult for me.