An I the only person who imagines domes are not that prevalent? I think of them as the lowest levels of the palimpsest, the 'lunar bases' that were built upon more than 15,000 years ago. That's why you only hear of 'collapsed' domes.
In my head of goes something like:
Small domes, connected into complexes, remodeled with abandoned wings, forgotten and covered with ash, better tech-level colony built on top, and from there its all Tudor-style jetties and Edinburgh-style streets above streets. As the bottom layers collapse the outside walls are fortified to keep the top safe, thus the Underhive
In my head of goes something like:
Small domes, connected into complexes, remodeled with abandoned wings, forgotten and covered with ash, better tech-level colony built on top, and from there its all Tudor-style jetties and Edinburgh-style streets above streets. As the bottom layers collapse the outside walls are fortified to keep the top safe, thus the Underhive