Read this:
777X Configuration Changes Revealed | Commercial Aviation content from Aviation Week
I can't see the 748 coming. It's a four-legged dinosaur, just as is the dugong.
AS per a LH colleague, the performance per nm/lb seems almost equal on 380, 77W and 748 (all in the LH extended fleet), which says it all: Two 5 year old marvels can only match a 25 year old. Impressive not.
Physics are the limit and transporting too much dead weight will punish you, even being the most fervent 380 or 748 fan.
Even Airbus rightfully sees the 77X as the most serious enemy (see article), not only for the 350, but even more for the 380. Upgrading it with new engines is pretty much futile, it does not fight the initial design handicap. Their reluctance to go ahead is therefore understandable, the resources have to go to the 350, to make it able to compete with the 77X. EK's offloading of the actual 350 says it all.
Wait for EK to cancel the last 50 380's if there is no re-engine program coming. Maybe not today, but when the "Asian face rubbing" fades out, the oil price picks up even more and the customers get a little scarcer and finally when the initial subsidies by cheap purchasing and leasing evaporates, i can see Timmy's successor correct some arrogant over-eagerness of today's management.
If there would be anything taking a space of a 380, it would certainly not be a 748.