because the cost of the perceived high-value solution (fuel) is so much cheaper for them than their competitors?
EK pays pretty much the same as everybody else for fuel. They would get some volume discounts, but that is probably about it.
The reason I say that is that they never tanker fuel out of Dubai. Not even for a short ME or India turn. If fuel was that much cheaper in Dubai, they would be tankering as much as possible out of there.