Can Gulf carriers sustain their rapid growth?

The startling rise of Emirates, Etihad, and Qatar Airways has reshaped global aviation markets around the three hubs of Dubai, Abu Dhabi, and Doha as the Gulf airlines have developed into what the Economist magazine has labelled “global super-connectors” capable of connecting any two points in the world with one stopover in the Gulf. Can the Gulf can sustain three aggressively expanding airlines within such a concentrated region (and market)?