Empire4, it looks like your ego is getting in the way of facts. You appear to look at a person's rank to estimate his/her worth. A QF S/O is as much a pilot (& may even have better skills) as one who joins Jetstar, Virgin, Tiger etc as a F/O. The fact that they don't yet get the opportunity to carry out take-offs and landings on the large widebody aircraft that they are rated on doesn't make them less valuable to the operation than an A320/B737 F/O.
The reason QF has been prepared (in the past) to pay the S/O's well is to attract the best people. If that level of remuneration was not available, these pilots would become domestic F/O's instead of joining QF.