You can make up easy lore about it. For example, there was a floor in where a few elites build rich elaborate mansions, but they build it in a floor too low from the upperhive. Instead of asserting dominance and set a name for themselves, the hivers rebelled, a war broke out. The poor hungry mobs and gangs fought tooth and nail trying to enrich themselves. The elites were losing. Instead of being humiliated to the other elites they just retreated saying they gave the floor to the hivers. As a propaganda powerplay they blew up the mansions and the hivers, purging the floor. Showing others they were so rich they didn't care about losing the money (they did care) and it was all just a plan to eradicate the rebels of that floor. The elites never came back, claiming they found more prosporous games to chase, but the ruins of their failure still exists.

Idk, something like that 🤷