Other Chantries may be up and coming, and different factions may have different centers. Cordoba may not do much good against the technomancers, but the traditional hermetics are protecting it and its treasures. I prefer to think of the "central Chantries" as the largest, and currently most influential, Chantries. How long did it take Verbena members to travel to Schwartzwald from India in the 10th century? To run a central Chantry the Tradition must also be able to communicate, and to travel to it. Order of Hermes is split into many factions. Euthanatos and Verbena certainly are very disorganized except on the local level. Cult of Ecstasy is quite different in the East and West (compare a Tantric mage with the pot-smoking rebel in Berkeley). Akashic Brotherhood seems to be divided into many sects, each with its own center. Many Traditions do not have any central organization. I also think that the idea of central Chantries is somewhat flawed. In less Technocracy-influenced areas, they do not cooperate ("What? Would we, the True Tantric Brotherhood of Bombay cooperate with you, the Sisters of Delight? Begone, impure!") Originally they were many disparate groups, which have been forced to work together against their mutual enemy. Maybe the Traditions as described are the Western alliances against the Technocracy.
Even with the technomancer threat, many groups will not cooperate with the "Traditions". I think the idea of well organized, cooperating traditions is simply not working. The traditions describe a western perspective of multicultural groupings with similar methods. A shaman from the Aleutian tribes would recognize parts of the magick of an African medicine man, but would probably disagree quite a bit with him about how the universe worked and what the spirits wanted. There were mages at the Emperor's court in China who were most definitely hermetic, but completely unlike the western hermetics. To some extent, the Traditions described are just groupings of mages with similar methods. My players repeatedly point out that I have a hermetic bias. After all, it is hard for most players to relate to traditions completely outside their own culture (I personally feel quite out of my depth when discussing the Akashic Brotherhood, Dreamspeakers and Hollow Ones. Mostly I think it is because White Wolf doesn't know enough about possible traditions from other cultures, and neither do most players (what traditions exist in the Philippines?). To some extent this can be explained by assuming the European traditions have expanded in the wake of the Technomancers (see my posting about the Technocracy's methods). I agree completely that White Wolf has made the Traditions too Western.