People generally don't quit for two reasons:
1. Seniority. You go somewhere else you are back at the bottom.
2. Major airlines like CX, BA, etc etc all offer similar packages these days. The 5 or 10 % more pay at another company is just not worth swopping one set of problems for another.
Reality is that once you get to a big jet your flying days are over. Almost everybody here enjoyed flying before they got to the airline. What we enjoy now is going to work as little as possible. We enjoy the company of our fellow pilots - mostly. We enjoy not being tied to a desk. We enjoy the satisfaction of a flight well done in sometimes trying conditions. But we don't enjoy much flying anymore.