Its far more basic than the above. Would you want to work for a company that would give a better job to someone outside rather than those that have already joined.
This seems to be the sticking point with many pilots in EK now. They joined on a fleet that was having the good rosters and with commands happening in good time, knowing that others already in the company were being shafted roster wise and had been waiting over 7yrs for a command opportunity. But hey, that ****e was happening to someone else right? Now that some of the less enjoyable flying and rostering practices are heading their way, and commands have slowed, they squeal like a halal pig.
380 rosters/lifestyle might be ok now, but EK history proves it doesn't take too long to change. It never seems to change for the good.