All of the big Bullfrog games were unique and for some reason never spawned imitators. Populous, Magic Carpet, Theme Park/Hospital, Dungeon Keeper alongside Syndicate
Man I really miss Populous, the whole feel of that game was just so unique and fantastic.
Dungeon Keeper absolutely produced knockoffs. Orcs Must Die, Dungeon Defenders, Dungeons, etc.
There are plenty of theme park and dungeon sims now. Even Syndicate has a spiritual successor made by former syndicate devs
They definitely are successors to some of those. Two Point Hospital for one.
It never quite recaptured the charm of the original, but that might just be because I’m older.