Very well thought out post. Insightful analysis. In any regular airline, FO's transition from smaller aircraft to bigger aircraft, come back down to the smaller aircraft to get a command, hone their command skills and transition back to the bigger fleet.
Whilst that is not possible in EK, because they dont have smaller aircraft, it doesnt mean EK FO's are any better than the others in the industry.
As I have observed, a lot of them come from smaller regional carriers (stop taking pictures of meal trays to send back to your buddies
, I know your old airlines didnt serve "proper meals", or had crockery!!) , and are still able to transition onto a bigger aircraft and fly the global network. DEC whether from smaller aircraft or smaller airlines can still transition.
Proper Training, proper preparation, adequate resources, and a high sense of professionalism will make this possible.