Buzz,
EK have a couple of 380s. They send 5 a day to LHR, two a day to LGW. They are full, and fares are equal to or more than the competition. They also send two in MAN, and one into BHX a day. Seems you can still keep up frequency with a larger aircraft and not kill the yield.
DXB is slot/gate limited and they have no choice but go to larger aircraft if they still want to grow.