Final answer:
American cities have transitioned from privately owned utilities to publicly owned or regulated monopolies due to municipal socialism, state-granted municipal powers, encouragement of public benefit systems, and the nature of the mixed economy.
Step-by-step explanation:
Today, only a dozen or so American cities have separately owned and fully publicly owned utilities, compared to 502 cities in 1923. The transition from multiple competing utilities to what is now common—a regulated monopoly—can be traced to several factors. First, the growth of municipal socialism in the early 20th century saw many city governments taking over existing services to create publicly owned infrastructure like streetcar lines and public works. Second, municipalities often have the authority granted by the state to manage local utilities and influence residents' lives significantly. Additionally, there has been a shift towards government-encouraged development of utility systems for the public benefit. Lastly, from a broader perspective, American municipalities typically operate within a mixed economy, where key industries might be nationalized but most businesses remain private, yet government-regulated. The shift to subsidized, regulated monopolies in city bus companies and other utilities can thus be understood as part of this larger context of governmental involvement to ensure public access and moderate costs.