Hmm. Another issue is: just how many big airlines can survive in what is a very small region of the world? The Gulf is certainly a good place for a "global" hub - a meeting point for Europe, North and South Asia, Africa, Oceania (though not the Americas). But four global airlines? Naah, something has to give. With the exception of oil, all it has to offer is secondary service industries - it doesn't have a home market (wealth concentrated in the hands of a relative few, who often have private travel arrangements anyway), it doesn't even have a significant financial market.
In the medium to long term (15-20 years?), I'd suggest that at most two airlines will continue to thrive, if the Airbus view of the world (A380's) dominates. But if the Boeing (B7E7) view dominates, the Gulf will gradually disappear into obscurity again.