Instead, EK wants to continue to expand and double it's size by 2020
Where do you get that from? Current planning (and aircraft orders) is nowhere near doubling the fleet. Tim Clark has stated numerous times in the recent past that he sees the airline at around 270 aircraft by 2020. We have ~210 now.
See here for a recent statement:
By 2020, we will have more than 250 aircraft serving some 70 million passengers across six continents