OpenTTD isn’t a Sim City copy. Its a reimplement of Transport Tycoon. It’s a strategy game that focuses on business that covers multiple cities and industrial works. While city builders are a subset of strategy games, not all strategy sims are city builders. Examples of how the strategy genre covers more than just city builders would be: Theme Park, The Settlers, Theme Hospital, Railroad Tycoon, Populous, Command & Conquerer and Civilisation.

Sim City isn’t even the first city builder, let along first strategy sim. The genre has existed since the days of text-based games. Though it’s fair to say Sim City is one of the most iconic and successful entries in the genre.