The whole argument regarding seniority for pilots versus merit with doctors, lawyers and other office-wallahs usually misses the point. In most hospitals you have some doctors. In a law firm you'll have a couple of partners. In an airline you have hundreds if not thousands of pilots.
This is the difference!!!!!! Numbers!!!! Oh poor lowly F/Os who are bitching here about the system... It's life. Accept that this is how aviation works. Personally, as a XX,000hr Captain I would expect (correctly) to join the bottom of the list if I went to CX or SQ... End of story!