Is that analogy necessarily parallel to networking? The radio station communicates with an entire city. The traffic jam only affects traffic within X miles of the bottle neck. I can imagine a car radio that automatically stitches to a local radio station that only broadcasts traffic jams that are relevant to cars in that area, eliminating the need for a larger centralized station.
Well, I think any analogy starts to fall apart when you look too closely. But you've got the right idea. Sure, there's no reason you couldn't distribute it out further. I used the word 'entity' above in an attempt to imply that it could be "one large radio station" or "a group of smaller radio stations"--the point is that the decision-making is abstracted out to somewhere else.
Note also the use of "logically centralized", not "physically centralized".
