Have a look at Egyption mythology. Each of the gods was patron of a particular city, and many of the myths about the gods are actually metaphors for the fortunes of the cities they represent. When a city became the new capital, for example, the myhts might associate its god with the highest deity (often in a familial way) (e.g. Horus). If a city lost favor with the king or priesthood, its god might be vilified in myth (e.g. Set). The same is true of Mesoporamian myth, Central American, and I suspect many others. The idea of a god's power (in the greater scheme, not to an inidiviual worshipper) being linked to his poularity is not a new concept.