Quite right Plane and Simple. They are both the right aircraft for EK to have in the fleet - but there are just far tooo many of them. You need a smaller (single aisle?) aircraft to plough some of the thinner routes when pax numbers just don't justify the big birds, or for seasonal variation etc etc.
Surely at the end of the day the biggest victory you can have over your competition is to be the richest not just the biggest!