"I suppose most guys here with 10 years in EK are of an age that would make it difficult for them to reach the mentioned "Capt 777 at Delta" position if they move home so that comparison might not be relevant."
No one assumes you'd leave EK and step into the same job in the US.
Guys with 10 years at EK have already been a B777 skipper and made the money. Been there, done that. If you NEED to make that still when you go home perhaps you haven't managed your money as well as you could have. (Or have a lot of ex-wives!) But that's another topic.