The fact is DEC's have and will be at EK forever. Would not be surprised if the current add changes to 330/777 to see if the response increases . I can also see 380 DEC's if and when the response for the 330/777 drops.
Don't think that lack of qualified FO applications will slow the expansion. It will only slow the upgrades.
Pilots are not a valued commodity . You can and will be replaced by a cheaper new hire be it FO or DEC.