AT&T, pre-Internet, had 10 major regions in the US, and switches had a fixed list of primary, secondary, and tertiary routes. The first "centralization" was simply that the priorities in the routing tables were changed every few minutes based on load. But if the central routing planner went down or was unreachable, everything still worked, just not as optimally.

What you don't want is software-defined networking where every new flow goes to Master Control for validation and routing. Some SDN systems do that, and they have a central point of failure and censorship.