decentralization is taking back some of the control back from central authorities. The problem is people often do not want to be 100% responsible for their own well being. This in turn leads to re-centralization at some point. We have governments because people often do not believe they can easily live together with complete trust. We have laws in order to make it easier for humans to live together. Essentially offloading a cognitive function of threat detection by relying on a trusted entity (government) to create a safe environment. In a dictatorship its possible for that trusted entity to transform into a bad faith actor and no longer work towards its original purpose. We introduce democracy/republicanism (a form of decentralization) in order to protect against this flaw. This form of government itself often re-centralizes in some form or another (government parties).
What I'm trying to get at is that while centralization is efficient and many things head to centralization we should still try to make the backbone decentralized whenever possible. It is a form protection against a central authority transitioning to a bad faith actor. Almost all central authorities will eventually transition to bad faith (from the end users perspective). With as much of the backbone being decentralized as possible we can at least more easily finger point and hold those central authorities responsible for their actions.