Not everyone wants to fly round the world, watching an auto-pilot.
There is something pure and enjoyable about actually FLYING a plane, and the lifestyle is very different. Some care about $$, some QOL, some the job.
The old saying different strokes for different folks! Ever notice the bottom 1/3 of the seniority list has a high turnover, but the top third is all longer term?
Lots of people find reasons to stay....and a few flew RJ's and left commuters to fly for AMF.
The grass always seems greener on the other side of the fence, but watch out, it might be greener just because it's over the septic tank......