Who runs the network?

Could you please elaborate on the question of who exactly runs the cryptocurrency network? Is it a centralized entity, like a bank or government, or is it decentralized, with no single point of control? If it's decentralized, how does the network function without a central authority? Are there any organizations or groups that play a significant role in maintaining the network, and if so, what are their responsibilities? Understanding the structure and operation of the network is crucial for assessing its security, stability, and long-term viability.