Lowpass,
I agree on most points but you're possibly mistaken on one. It has been explained to me, by someone whose son was a cadet (that keeps the field pretty large!) that cadets actually cost the company nothing; why? Because the cost of their course, in whatever its form, includes not only flyng and ATPL subject fees but the $X000 psychometric assessment, sim time, clerical expenses etc. They are also viewed strongly to offer the prospect of greater allegience to QF for more years.
Does all that still make sense?... not to me really, when there are many capable pilots already out there with the requisite experience, but that's finances for you.