I'd guess most of the pilots leaving EK these days are indeed US types.
There are something like 90 different nationalities at EK on the flight deck and if you looked at most of the countries these fine aviators come from, you'll realize their home country may not be having the hiring boom that your country is currently having. That and a few other reasons are why they aren't leaving in droves…. Most of it being family issues. "The family likes it here" is what I hear mostly. The longer one stays in Dubai, the more you just learn to understand how to get along here, how to survive the antics of EK etc. I get the sense that many are content at EK due to the good quality schools , growing up in an international environment which certainly expands the minds of children, the many friends you'll make in Dubai in the close knit communities lived in.
I've always been amazed that some are able to completely adapt to everything in Dubai and EK… while others can't wait for the bond to expire and leave the day after!
K